Under the Hood: Demystifying Docker For Mac CE Edition

Estimated Reading Time: 6 minutes

 

Docker is a full development platform for creating containerized apps, and Docker for Mac is the most efficient way to start and run Docker on your MacBook. It runs on a LinuxKit VM and NOT on VirtualBox or VMware Fusion. It embeds a hypervisor (based on xhyve), a Linux distribution which runs on LinuxKit and filesystem & network sharing that is much more Mac native. It is a Mac native application, that you install in /Applications. At installation time, it creates symlinks in /usr/local/bin for docker & docker-compose and others, to the commands in the application bundle, in /Applications/Docker.app/Contents/Resources/bin.

One of the most amazing feature about Docker for Mac is “drag & Drop” the Mac application to /Applications to run Docker CLI and it just works flawlessly. The way the filesystem sharing maps OSX volumes seamlessly into Linux containers and remapping macOS UIDs into Linux is one of the most anticipated feature.

Few Notables Features of Docker for Mac:

  • Docker for Mac runs in a LinuxKit VM.
  • Docker for Mac uses HyperKit instead of Virtual Box. Hyperkit is a lightweight macOS virtualization solution built on top of Hypervisor.framework in macOS 10.10 Yosemite and higher.
  • Docker for Mac does not use docker-machine to provision its VM. The Docker Engine API is exposed on a socket available to the Mac host at /var/run/docker.sock. This is the default location Docker and Docker Compose clients use to connect to the Docker daemon, so you to use docker and docker-compose CLI commands on your Mac.
  • When you install Docker for Mac, machines created with Docker Machine are not affected.
  • There is no docker0 bridge on macOS. Because of the way networking is implemented in Docker for Mac, you cannot see a docker0 interface on the host. This interface is actually within the virtual machine.
  • Docker for Mac has now Multi-Architectural support. It provides binfmt_misc multi architecture support, so you can run containers for different Linux architectures, such as arm, mips, ppc64le, and even s390x.

Top 5 Exclusive Features of Docker For Mac That You Can’t Afford to Ignore

Under this blog, I will deep dive into Docker for Mac architecture and show how to access service containers running on top of LinuxKit VM.

At the base of architecture, we have hypervisor called Hyperkit which is derived from xhyve. The xhyve hypervisor is a port of bhyve to OS X. It is built on top of Hypervisor.framework in OS X 10.10 Yosemite and higher, runs entirely in userspace, and has no other dependencies. HyperKit is basically a toolkit for embedding hypervisor capabilities in your application. It includes a complete hypervisor optimized for lightweight virtual machines and container deployment. It is designed to be interfaced with higher-level components such as the VPNKit and DataKit.

Just sitting next to HyperKit is Filesystem sharing solution. The osxfs is a new shared file system solution, exclusive to Docker for Mac. osxfs provides a close-to-native user experience for bind mounting macOS file system trees into Docker containers. To this end, osxfs features a number of unique capabilities as well as differences from a classical Linux file system.On macOS Sierra and lower, the default file system is HFS+. On macOS High Sierra, the default file system is APFS.With the recent release, NFS Volume sharing has been enabled both for Swarm & Kubernetes.

There is one more important component sitting next to Hyperkit, rightly called as VPNKit. VPNKit is a part of HyperKit attempts to work nicely with VPN software by intercepting the VM traffic at the Ethernet level, parsing and understanding protocols like NTP, DNS, UDP, TCP and doing the “right thing” with respect to the host’s VPN configuration. VPNKit operates by reconstructing Ethernet traffic from the VM and translating it into the relevant socket API calls on OSX. This allows the host application to generate traffic without requiring low-level Ethernet bridging support.

On top of these open source components, we have LinuxKit VM which runs containerd and service containers which includes Docker Engine to run service containers. LinuxKit VM is built based on YAML file. The docker-for-mac.yml contains an example use of the open source components of Docker for Mac. The example has support for controlling dockerd from the host via vsudd and port forwarding with VPNKit. It requires HyperKit, VPNKit and a Docker client on the host to run.

Sitting next to Docker CE service containers, we have kubelet binaries running inside LinuxKit VM. If you are new to K8s, kubelet is an agent that runs on each node in the cluster. It makes sure that containers are running in a pod. It basically takes a set of PodSpecs that are provided through various mechanisms and ensures that the containers described in those PodSpecs are running and healthy. The kubelet doesn’t manage containers which were not created by Kubernetes.On top of Kubelet, we have kubernetes services running. We can either run Swarm Cluster or Kubernetes Cluster. We can use the same Compose YAML file to bring up both the clusters side by side.

Peeping into LinuxKit VM

Curious about VM and how Docker for Mac CE Edition actually look like?

Below are the list of commands which you can leverage to get into LinuxKit VM and see kubernetes services up and running. Here you go..

How to enter into LinuxKit VM?

Open MacOS terminal and run the below command to enter into LinuxKit VM:

$screen ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/tty

Listing out the service containers:

Earlier the ctr tasks ls used to list the service containers running inside LinuxKit VM but in the recent release, namespace concept has been introduced, hence you might need to run the below command to list out the service containers:

$ ctr -n services.linuxkit tasks ls
TASK                    PID     STATUS
acpid                   854     RUNNING
diagnose                898     RUNNING
docker-ce               936     RUNNING
host-timesync-daemon    984     RUNNING
ntpd                    1025    RUNNING
trim-after-delete       1106    RUNNING
vpnkit-forwarder        1157    RUNNING
vsudd                   1198    RUNNING

How to display containerd version?

Under Docker for Mac 18.05 RC1, containerd version 1.0.1 is available as shown below:

linuxkit-025000000001:~# ctr version
Client:
  Version:  v1.0.1
  Revision: 9b55aab90508bd389d7654c4baf173a981477d55

Server:
  Version:  v1.0.1
  Revision: 9b55aab90508bd389d7654c4baf173a981477d55
linuxkit-025000000001:~#

How shall I enter into docker-ce service container using containerd?

ctr -n services.linuxkit tasks exec -t --exec-id 936 docker-ce sh
/ # docker version
Client:
 Version:      18.05.0-ce-rc1
 API version:  1.37
 Go version:   go1.9.5
 Git commit:   33f00ce
 Built:        Thu Apr 26 00:58:14 2018
 OS/Arch:      linux/amd64
 Experimental: false
 Orchestrator: swarm

Server:
 Engine:
  Version:      18.05.0-ce-rc1
  API version:  1.37 (minimum version 1.12)
  Go version:   go1.10.1
  Git commit:   33f00ce
  Built:        Thu Apr 26 01:06:49 2018
  OS/Arch:      linux/amd64
  Experimental: true
/ #

How to verify Kubernetes Single Node Cluster?

/ # kubectl version
Client Version: version.Info{Major:"1", Minor:"9", GitVersion:"v1.9.6", GitCommit:"9f8ebd171479bec0ada837d7ee641dec2f8c6dd1", GitTreeState:"clean", BuildDate:"2018-03-23T09:38:59Z", GoVersion:"go1.9.4", Compiler:"gc", Platform:"linux/amd64"}
Server Version: version.Info{Major:"1", Minor:"9", GitVersion:"v1.9.6", GitCommit:"9f8ebd171479bec0ada837d7ee641dec2f8c6dd1", GitTreeState:"clean", BuildDate:"2018-03-21T15:13:31Z", GoVersion:"go1.9.3", Compiler:"gc", Platform:"linux/amd64"}
/ # kubectl get nodes
NAME                 STATUS    ROLES     AGE       VERSION
docker-for-desktop   Ready     master    26d       v1.9.6
/ #

 

Interested to read further? Check out my curated list of blog posts –

Docker for Mac is built with LinuxKit. How to access the LinuxKit VM
Top 5 Exclusive Features of Docker for Mac That you can’t afford to ignore
5 Minutes to Bootstrap Kubernetes Cluster on GKE using Docker for Mac 18.03.0
Context Switching Made Easy under Kubernetes powered Docker for Mac 18.02.0
2-minutes to Kubernetes Cluster on Docker for Mac 18.01 using Swarm CLI
Docker For Mac 1.13.0 brings support for macOS Sierra, now runs ARM & AARCH64 based Docker containers
Docker for Mac 18.03.0 now comes with NFS Volume Sharing Support for Kubernetes

 

Did you find this blog helpful?  Feel free to share your experience. Get in touch with me at twitter @ajeetsraina.

If you are looking out for contribution/discussion, join me at Docker Community Slack Channel.

3
0

Top 5 Exclusive Features of Docker For Mac That You Can’t Afford to Ignore

Estimated Reading Time: 7 minutes

 

Docker for Mac 18.04.0 CE Edge Release went GA early last month. This was the first time Kubernetes version 1.9.6 & Docker Compose 1.21.0 was introduced under any Docker Desktop edition. ICYMI – Docker for Mac VM is entirely built with LinuxKit, hence this was the first release which enabled the RBD and CephFS kernel modules under LinuxKit VM. In case you’re new to RBD, the linux kernel RBD (rados block device) driver allows striping a linux block device over multiple distributed object store data objects. Usually the libceph module takes care of that.This release brought a number of fixes around upgrades from Docker for Mac 17.12, synchronisation between CLI `docker login` & GUI login, support for AUFS and much more.

Under this blog post, I will talk about top 5 exclusive and very useful features of Docker of Mac that you can’t afford to miss out.

#1: Docker for Mac support Docker Swarm, Swarm Mode & Kubernetes

Starting from Docker for Mac 17.12 CE Edge Release, Docker Inc introduced a standalone Kubernetes server and client, as well as Docker CLI integration. The Kubernetes server runs locally within your Docker instance, is not configurable, and is a single-node cluster.

One of the most anticipated feature introduced with this release was the Kubernetes server running within a Docker container on your local system. When Kubernetes support is enabled, you can deploy your workloads, in parallel, on Kubernetes, Swarm, and as standalone containers. Enabling or disabling the Kubernetes server does not affect your other workloads.

You can use Docker for Mac to test single-node features of swarm mode introduced with Docker Engine 17.12, including initializing a swarm with a single node, creating services, and scaling services. Docker “Moby” on Hyperkit serves as the single swarm node. You can also use Docker Machine, which comes with Docker for Mac, to create and experiment a multi-node swarm.

While testing Kubernetes, you may want to deploy some workloads in swarm mode. You can use the DOCKER_ORCHESTRATOR variable to override the default orchestrator for a given terminal session or a single Docker command. This variable can be unset (the default, in which case Kubernetes is the orchestrator) or set to swarm or kubernetes.

 

Check out my blog post:

2-minutes to Kubernetes Cluster on Docker for Mac 18.01 using Swarm CLI

 

#2:  You can use the same Docker Compose to build Swarm & Kubernetes Cluster

Yes, you read it correct. Starting from Docker for Mac 17.12, Docker introduced a new type called “Stack” under compose.docker.com. This object, that you can create with kubectl or more easily with docker stack deploy, contains the compose file.Behind the scene, a controller watches for stacks and create/update corresponding kubernetes objets (deployments, services, etc). The job of the controller is to reconcile the stacks (stored in the api-server or crd) with k8s native object.

The docker stack deploy manages to deploy to K8s. It convert docker-compose files to k8s manifests (something like kompose) before deployment. Let me showcase an example which shows how one can use the same YAML file to build Swarm Mode as well as K8s cluster.

Clone the Repository

$git clone https://github.com/ajeetraina/docker101

Change to the right location

$cd docker101/play-with-kubernetes/examples/stack-deploy-on-mac/

Example-1 : Demonstrating a Simple Web Application

Building the Web Application Stack

$docker stack deploy -c docker-stack1.yml myapp1

Verifying the Stack

$docker stack ls

Verifying using Kubectl

$kubectl get pods

Verifying if the web application is accessible

$curl localhost:8083

Cleaning up the Stack

$docker stack rm myapp`

Example:2 – Demonstrating ReplicaSet

Building the Web Application Stack

$docker stack deploy -c docker-stack2.yml myapp2

Verifying the Stack

$docker stack ls

Verifying using Kubectl

$kubectl get pods
Ajeets-MacBook-Air:testenviron ajeetraina$ kubectl get stacks
NAME      AGE
myapp2    22m
Ajeets-MacBook-Air:testenviron ajeetraina$ kubectl get pods
NAME                    READY     STATUS    RESTARTS   AGE
db1-d977d5f48-l6v9d     1/1       Running   0          22m
db1-d977d5f48-mpd25     1/1       Running   0          22m
web1-6886bb478f-s7mvz   1/1       Running   0          22m
web1-6886bb478f-wh824   1/1       Running   0          22m
Ajeets-MacBook-Air:testenviron ajeetraina$ kubectl get stacks myapp2 -o yaml
apiVersion: compose.docker.com/v1beta2
kind: Stack
metadata:
  creationTimestamp: 2018-01-28T02:55:28Z
  name: myapp2
  namespace: default
  resourceVersion: "3186"
  selfLink: /apis/compose.docker.com/v1beta2/namespaces/default/stacks/myapp2
  uid: b25bf776-03d6-11e8-8d4c-025000000001
spec:
  stack:
    Configs: {}
    Networks: {}
    Secrets: {}
    Services:
    ..
      WorkingDir: ""
    Volumes: {}
status:
  message: Stack is started
  phase: Available

Verifying if the web application is accessible

$curl localhost:8083

Cleaning up the Stack

$docker stack rm myapp2

An Interesting Read:

5 Minutes to Bootstrap Kubernetes Cluster on GKE using Docker for Mac 18.03.0

#3:  Docker for Mac provides Multi-Architecture Support

Docker for Mac provides binfmt_misc multi architecture support. This means that now you can run containers for different Linux architectures, such as arm, mips, ppc64le, and even s390x.

#4:  Support for NFS Volume sharing under Swarm as well as Kubernetes

With Docker for Mac 18.03 release, NFS Volume sharing support for both Swarm & Kubernetes was introduced. To demonstrate this feature, follow the below steps:

Pre-Requisite:

  • Install Docker for Mac 18.03 and future version
  • Enable Kubernetes under Preference Pane UI

Cloning the Repository

git clone https://github.com/ajeetraina/docker101/
cd docker101/for-mac/nfs

Execute the below script on your macOS system

sh env_vars.sh
sh setup_native_nfs_docker_osx.sh

 +-----------------------------+
 | Setup native NFS for Docker |
 +-----------------------------+

WARNING: This script will shut down running containers.

-n Do you wish to proceed? [y]:
y

== Stopping running docker containers...
== Resetting folder permissions...
Password:
== Setting up nfs...
== Restarting nfsd...
The nfsd service does not appear to be running.
Starting the nfsd service
== Restarting docker...

SUCCESS! Now go run your containers 🐳

Bringing up Your Application

docker stack deploy -c docker-compose.yml myapp2
 docker stack ls
NAME                SERVICES
myapp2                1
[Captains-Bay]🚩 >  kubectl get po
NAME      READY     STATUS    RESTARTS   AGE
web-0     1/1       Running   0          3m
[Captains-Bay]🚩 >  kubectl get svc
NAME         TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)     AGE
kubernetes   ClusterIP   10.96.0.1    <none>        443/TCP     1d
web          ClusterIP   None         <none>        55555/TCP   3m
[Captains-Bay]🚩 >  kubectl describe po web-0
Name:           web-0
Namespace:      default
Node:           docker-for-desktop/192.168.65.3
Start Time:     Wed, 11 Apr 2018 23:00:18 +0530
Labels:         com.docker.service.id=up2u-web
                com.docker.service.name=web
                com.docker.stack.namespace=up2u
                controller-revision-hash=web-7dbbf8689d
                statefulset.kubernetes.io/pod-name=web-0
Annotations:    <none>
Status:         Running
IP:             10.1.0.34
Controlled By:  StatefulSet/web
Containers:
  web:
    Container ID:  docker://ec9ad2a3192bdeb0cc5028453310f40fd0ac3595021b070465c4e7725f626d63
    Image:         alpine:3.6
    Image ID:      docker-pullable://alpine@sha256:3d44fa76c2c83ed9296e4508b436ff583397cac0f4bad85c2b4ecc193ddb5106
    Port:          <none>
    Args:
      ping
      127.0.0.1
    State:          Running
      Started:      Wed, 11 Apr 2018 23:00:19 +0530
    Ready:          True
    Restart Count:  0
    Environment:    <none>
    Mounts:
      #{CONTAINER_DIR} from nfsmount (rw)
      /var/run/secrets/kubernetes.io/serviceaccount from default-token-n8trf (ro)
Conditions:
  Type           Status
  Initialized    True
  Ready          True
  PodScheduled   True
Volumes:
  nfsmount:
    Type:       PersistentVolumeClaim (a reference to a PersistentVolumeClaim in the same namespace)
    ClaimName:  nfsmount-web-0
    ReadOnly:   false
  default-token-n8trf:
    Type:        Secret (a volume populated by a Secret)
    SecretName:  default-token-n8trf
    Optional:    false
QoS Class:       BestEffort
Node-Selectors:  <none>
Tolerations:     node.kubernetes.io/not-ready:NoExecute for 300s
                 node.kubernetes.io/unreachable:NoExecute for 300s
Events:
  Type    Reason                 Age   From                         Message
  ----    ------                 ----  ----                         -------
  Normal  Scheduled              5m    default-scheduler            Successfully assigned web-0 to docker-for-desktop
  Normal  SuccessfulMountVolume  5m    kubelet, docker-for-desktop  MountVolume.SetUp succeeded for volume "pvc-bbdc7903-3dad-11e8-a612-025000000001"
  Normal  SuccessfulMountVolume  5m    kubelet, docker-for-desktop  MountVolume.SetUp succeeded for volume "default-token-n8trf"
  Normal  Pulled                 5m    kubelet, docker-for-desktop  Container image "alpine:3.6" already present on machine
  Normal  Created                5m    kubelet, docker-for-desktop  Created container
  Normal  Started                5m    kubelet, docker-for-desktop  Started container

 

 

#5:  Docker for Mac support context switching from docker-for-desktop to Cloud instances in a matter of a Click

Starting from Docker for Mac 18.02 RC release, the context switching feature was introduced which helped developers and operators to switch from docker-for-desktop to any Cloud environment in just a matter of a “toggle”.

 

I have a detailed blog post published early this year which demonstrates this feature with crystal clear examples. Check it out.

Context Switching Made Easy under Kubernetes powered Docker for Mac 18.02.0

Other attractive features of Docker for Mac 18.04 includes –

  • Docker for Mac VM is entirely built with LinuxKit

How to enter into LinuxKit VM?

$screen ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/tty
/ # cat /etc/issue

Welcome to LinuxKit

                        ##         .
                  ## ## ##        ==
               ## ## ## ## ##    ===
           /"""""""""""""""""\___/ ===
          {                       /  ===-
           \______ O           __/
             \    \         __/
              \____\_______/
/ # cat /etc/os-release
PRETTY_NAME="Docker for Mac"
/ #
linuxkit-025000000001:~# cat /etc/os-release
PRETTY_NAME="Docker for Mac"
linuxkit-025000000001:~# runc list
ID                 PID         STATUS      BUNDLE                                CREATED                          OWNER
000-metadata       0           stopped     /containers/onboot/000-metadata       2018-05-05T06:27:44.345735031Z   root
001-sysfs          0           stopped     /containers/onboot/001-sysfs          2018-05-05T06:27:44.768313965Z   root
002-binfmt         0           stopped     /containers/onboot/002-binfmt         2018-05-05T06:27:45.630283593Z   root
003-format         0           stopped     /containers/onboot/003-format         2018-05-05T06:27:46.341011253Z   root
004-extend         0           stopped     /containers/onboot/004-extend         2018-05-05T06:27:47.08889973Z    root
005-mount          0           stopped     /containers/onboot/005-mount          2018-05-05T06:27:55.334088074Z   root
006-swap           0           stopped     /containers/onboot/006-swap           2018-05-05T06:27:56.486815308Z   root
007-ip             0           stopped     /containers/onboot/007-ip             2018-05-05T06:28:03.894591249Z   root
008-move-logs      0           stopped     /containers/onboot/008-move-logs      2018-05-05T06:28:05.980232896Z   root
009-sysctl         0           stopped     /containers/onboot/009-sysctl         2018-05-05T06:28:06.15775421Z    root
010-mount-vpnkit   0           stopped     /containers/onboot/010-mount-vpnkit   2018-05-05T06:28:06.356833391Z   root
011-bridge         0           stopped     /containers/onboot/011-bridge         2018-05-05T06:28:06.551619273Z   root
linuxkit-025000000001:~# ctr tasks ls
  • Docker for Mac uses raw format VM disks for systems running APFS on SSD on High Sierra by default
  • DNS name docker.for.mac.host.internal should be used instead of docker.for.mac.localhost (still valid) for host resolution from containers.

Did you find this blog helpful?  Feel free to share your experience. Get in touch with me at twitter @ajeetsraina.

If you are looking out for contribution/discussion, join me at Docker Community Slack Channel.

 

1
0

5 Minutes to Bootstrap Kubernetes Cluster on GKE using Docker for Mac 18.03.0

Estimated Reading Time: 7 minutes

Docker 18.03.0 CE Release is now available under Docker for Mac Platform. Docker for Mac 18.03.0 CE is now shipped with Docker Compose version 1.20.1, Kubernetes v1.9.2,  Docker Machine 0.14.0 & Notary 0.6.0.  Few of the promising features included under this release are listed below-

  • Changing VM Swap size under settings
  • Linux Kernel 4.9.87
  • Support of NFS Volume sharing under Kubernetes.
  • Revert the default disk format to qcow2 for users running macOS 10.13 (High Sierra).
  • DNS name `host.docker.internal` used for host resolution from containers.
  • Improvement over Kubernetes Load balanced services (No longer marked as `Pending`)
  • Fixed hostPath mounts in Kubernetes`.
  • Fix support for AUFS.
  • Fix synchronisation between CLI `docker login` and GUI login.
  • Updated Compose on Kubernetes to v0.3.0. Existing Kubernetes stacks will be removed during migration and need to be re-deployed on the cluster… and many more

In my last blog, I talked about context switching and showcased how one can switch the context from docker-for-desktop to Minikube under Docker for Mac Platform. A context element in a kubeconfig file is used to group access parameters under a convenient name. Each context has three parameters: cluster, namespace, and user. By default, the kubectl command-line tool uses parameters from the current context to communicate with the cluster. Under  .kube/config file, you can see the list of context specified a shown below –

– cluster:
certificate-authority-data: LS0tLS1CRUdJTiBDRVJUSUZJQ0FURS0tLS0tCk1JSURERENDQWZTZ0F3SUJBZ0lSQUpwcmVPY..V0gKZ0hVaVl6dGR…
server: https://35.201.215.156
name: gke_spheric-temple-187614_asia-east1-a_k8s-lab1
– cluster:
certificate-authority-data: LS0tLS1CRUdJTiBDRVJUSUZJQ0FURS0tLS0tCk1JSUN5RENDQWJDZ0F3SUJBZ0lCQURBTkJna3Foa2lHOOd2..LQo=
server: https://localhost:6443
name: kubernetes
– cluster:
certificate-authority: /Users/ajeetraina/.minikube/ca.crt
server: https://192.168.99.100:8443
name: minikube
contexts:
– context:
cluster: docker-for-desktop-cluster
user: docker-for-desktop
name: docker-for-desktop

Under this blog, I will showcase how you can bootstrap Kubernetes Cluster on GKE Platform using context switching functionality under Docker for Mac Platform.

Pre-requisite:

  • Install/Upgrade Docker for Mac 18.03 CE Edition
  • Install google-cloud-sdk
  • Enable Google Cloud Engine API
  • Authenticate Your Google Cloud using gcloud auth

Installing Docker for Mac 18.03 CE Edition

Installing Google Cloud SDK on your macOS

  • Make sure that Python 2.7 is installed on your system:

Ajeets-MacBook-Air:~ ajeetraina$ python -V
Python 2.7.10
  • Download the below package based on your system.
Platform Package Size SHA256 Checksum
macOS 64-bit(x86_64) google-cloud-sdk-195.0.0-darwin-x86_64.tar.gz 15.0 MB 56d72895dfc6c4208ca6599292aff629e357ad517e6979203a68a3a8ca5f6cc8
macOS 32-bit(x86) google-cloud-sdk-195.0.0-darwin-x86.tar.gz 15.0 MB e389ec98b65a0dbfc3f2c2637b9e3a375913b39d50e668fecb07cd04474fc080
  • Extract the archive to any location on your file system.
./google-cloud-sdk/install.sh
  • Restart your terminal for the changes to take effect.

Initializing the SDK

gcloud init

In your browser, log in to your Google user account when prompted and click Allow to grant permission to access Google Cloud Platform resources.

Enabling Kubernetes Engine API

You need to enable K8s engine API to bootstrap K8s cluster on Google Cloud Platform. To do so, open up this link.

Authenticate Your Google Cloud

Next, you need to authenticate your Google Cloud using glcloud auth

gcloud auth login

Done. We are all set to bootstrap K8s cluster…

Creating GKE Cluster Node

Ajeets-MacBook-Air:~ ajeetraina$ gcloud container clusters create k8s-lab1 --disk-size 10 --zone asia-east1-a --machine-type n1-standard-2 --num-nodes 3 --scopes compute-rw
WARNING: The behavior of --scopes will change in a future gcloud release: service-control and service-management scopes will no longer be added to what is specified in --scopes. To use these scopes, add them explicitly to --scopes. To use the new behavior, set container/new_scopes_behavior property (gcloud config set container/new_scopes_behavior true).
WARNING: Starting in Kubernetes v1.10, new clusters will no longer get compute-rw and storage-ro scopes added to what is specified in --scopes (though the latter will remain included in the default --scopes). To use these scopes, add them explicitly to --scopes. To use the new behavior, set container/new_scopes_behavior property (gcloud config set container/new_scopes_behavior true).
Creating cluster k8s-lab1...done.
Created [https://container.googleapis.com/v1/projects/spheric-temple-187614/zones/asia-east1-a/clusters/k8s-lab1].
To inspect the contents of your cluster, go to: https://console.cloud.google.com/kubernetes/workload_/gcloud/asia-east1-a/k8s-lab1?project=spheric-temple-187614
kubeconfig entry generated for k8s-lab1.
NAME      LOCATION      MASTER_VERSION  MASTER_IP       MACHINE_TYPE   NODE_VERSION  NUM_NODES  STATUS
k8s-lab1  asia-east1-a  1.7.11-gke.1    35.201.215.156  n1-standard-2  1.7.11-gke.1  3          RUNNING

Viewing it on Docker for Mac UI

Click on Whale icon on the top right of Docker for Mac and by now, you must be able to see the new Context getting appeared.

 

Listing the Nodes

 

Ajeets-MacBook-Air:~ ajeetraina$ kubectl get nodes
NAME                                      STATUS    ROLES     AGE       VERSION
gke-k8s-lab1-default-pool-042d2598-591g   Ready     <none>    7m        v1.7.11-gke.1
gke-k8s-lab1-default-pool-042d2598-c633   Ready     <none>    7m        v1.7.11-gke.1
gke-k8s-lab1-default-pool-042d2598-q603   Ready     <none>    7m        v1.7.11-gke.1

Viewing it directly under GCP Platform

 

 

Connecting to Your GKE Cluster

There are 2 ways to do this:

Method-1: Click on “Connection” button to see how to connect to K8s-lab1.

 

Method-2:

You can connect to your cluster via command-line or using a dashboard.

Ajeets-MacBook-Air:~ ajeetraina$gcloud container clusters get-credentials k8s-lab1 --zone asia-east1-a --project captain-199803
Fetching cluster endpoint and auth data.
kubeconfig entry generated for k8s-lab1. 

Fetching cluster endpoint and auth data. kubeconfig entry generated for k8s-lab1.

Listing the Nodes under Google Cloud Platform

 

Deploy Nginx on GKE Cluster

Let us see how to deploy Nginx on remote GKE cluster using Docker for Mac. This requires two commands. deploy and expose.

Step 1: Deploy nginx

$ kubectl run nginx --image=nginx --replicas=3

deployment "nginx" created

This will create a replication controller to spin up 3 pods, each pod runs the nginx container.

Step 2: Verify that the pods are running.

You can see the status of deployment by running:

kubectl get pods -owide
NAME                    READY     STATUS    RESTARTS   AGE       IP          NODE
nginx-7c87f569d-glczj   1/1       Running   0          8s        10.12.2.6   gke-k8s-lab1-default-pool-b2aaa29b-w904
nginx-7c87f569d-pll76   1/1       Running   0          8s        10.12.0.8   gke-k8s-lab1-default-pool-b2aaa29b-2gzh
nginx-7c87f569d-sf8z9   1/1       Running   0          8s        10.12.1.8   gke-k8s-lab1-default-pool-b2aaa29b-qpc7

Youcan see that each nginx pod is now running in a different node (virtual machine).

Once all pods have the Running status, you can then expose the nginx cluster as an external service.

Step 3: Expose the nginx cluster as an external service.

$ kubectl expose deployment nginx --port=80 --target-port=80 \
--type=LoadBalancer

service "nginx" exposed

This command will create a network load balancer to load balance traffic to the three nginx instances.

Step 4: Find the network load balancer address:

kubectl get service nginx
NAME      TYPE           CLUSTER-IP    EXTERNAL-IP   PORT(S)        AGE
nginx     LoadBalancer   10.15.247.8   <pending>     80:30253/TCP   12s

It may take several minutes to see the value of EXTERNAL_IP. If you don’t see it the first time with the above command, retry every minute or so until the value of EXTERNAL_IP is displayed.

You can then visit http://EXTERNAL_IP/ to see the server being served through network load balancing.

GKE provides amazing platform to view workloads & Load-balancer as shown below:

GKE also provides UI for displaying Loadbalancer:

In my upcoming blog post, I will showcase how context switching can help you in switching your project between Dev, QA & Production environment flawlessly.

Did you find this blog helpful? Feel free to share your experience. Get in touch with me on Twitter –  @ajeetsraina

If you are looking out for contribution, join me at Docker Community Slack Channel.

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Context Switching Made Easy under Kubernetes powered Docker for Mac 18.02.0

Estimated Reading Time: 7 minutes

Say Bye to Kubectx !

I have been a great fan of kubectx and kubectl which has been a fast way to switch between clusters and namespaces until I came across Docker for Mac 18.02. With the newer Docker for Mac 18.02 RC build, it is just a matter of a “toggle”. Life has become too easy to switch between dev, QA & production environment.

[Updated(2-Feb-2018) : Docker for Mac 18.02.0 CE RC2 build now comes with Kubernetes v1.9.2 for the first time. I upgraded my macOS High Sierra to RC2 build today and it just works flawlessly. Check it out]

 

New to Kubernetes Namespace Vs Context ?

Generally, software development teams partition their development pipelines into discrete units. These units take various forms in a discrete layout –

          Dev  >> Testing|QA >> Staging >> Production

The resulting layouts are ideally suited to Kubernetes Namespaces. Each environment or stage in the pipeline becomes a unique namespace.

In Kubernetes terminology, Namespaces are the way to partition a single Kubernetes cluster into multiple virtual clusters. Namespaces are a logical partitioning capability that enable one Kubernetes cluster to be used by multiple users, teams of users, or a single user with multiple applications without concern for undesired interaction. Each user, team of users, or application may exist within its Namespace, isolated from every other user of the cluster and operating as if it were the sole user of the cluster.

A major benefit of applying namespaces to the development cycle is that the naming of software components (e.g. micro-services/endpoints) can be maintained without collision across the different environments. This is due to the isolation of the Kubernetes namespaces. The fact that each namespace is logically discrete allows the development teams to work within an isolated “development” namespace.

Say, you have two clusters, one for development work and one for scratch work. In the development cluster, your frontend developers work in a namespace called frontend, and your storage developers work in a namespace called storage. In your scratch cluster, developers work in the default namespace, or they create auxiliary namespaces as they see fit. Access to the development cluster requires authentication by certificate. Access to the scratch cluster requires authentication by username and password.

Shown below is an example which clearly shows a file config-demo with this content:

apiVersion: v1
kind: Config
preferences: {}

clusters:
- cluster:
  name: development
- cluster:
  name: scratch

users:
- name: developer
- name: experimenter

contexts:
- context:
  name: dev-frontend
- context:
  name: dev-storage
- context:
  name: exp-scratch

As shown above, a configuration file describes clusters, users, and contexts. Your config-demo file has the framework to describe two clusters, two users, and three contexts.

Under this blog post, I will showcase how to create 3 difference contexts – Google Cloud, Docker for Desktop & Minikube first and then how easy is it to toggle between them under Docker for Mac Platform. Let’s get started –

Pre-requisite:

  • Docker For Mac 18.02 RC2 build

 

  • Enable Kubernetes under Preference Pane

Installing Minikube

Minikube requires that VT-x/AMD-v virtualization is enabled in BIOS. To check that this is enabled on OSX / macOS run:
sysctl -a | grep machdep.cpu.features | grep VMX

Installing Minikube via brew

Ajeets-MacBook-Air:~ ajeetraina$ brew update && brew install kubectl && brew cask install minikube

Starting Minikube

Ajeets-MacBook-Air:~ ajeetraina$ minikube start
Starting local Kubernetes v1.9.0 cluster...
Starting VM...
Downloading Minikube ISO
 142.22 MB / 142.22 MB [============================================] 100.00% 0s
Getting VM IP address...
Moving files into cluster...
Downloading localkube binary
 162.41 MB / 162.41 MB [============================================] 100.00% 0s
 0 B / 65 B [----------------------------------------------------------]   0.00%
 65 B / 65 B [======================================================] 100.00% 0sSetting up certs...
Connecting to cluster...
Setting up kubeconfig...
Starting cluster components...
Kubectl is now configured to use the cluster.
Loading cached images from config file.

Viewing Kubernetes context selection pane

By now, you should see Minikube context appear

Verifying it using CLI

Ajeets-MacBook-Air:~ ajeetraina$ kubectl config get-contexts
CURRENT   NAME                          CLUSTER                      AUTHINFO             NAMESPACE
         docker-for-desktop            docker-for-desktop-cluster   docker-for-desktop
         gce                                                        cluster-admin
         kubernetes-admin@kubernetes   kubernetes                   kubernetes-admin
*         minikube                      minikube                     minikube

Viewing Minikube Dashboard

You can just type the below command to bring up qinikube dashboard in a sec.

minikube dashboard

Initializing Docker Swarm

Ajeets-MacBook-Air:testenviron ajeetraina$ docker swarm init
Swarm initialized: current node (zfxiqqjpjmwbvhm1ahjwio3s7) is now a manager.

To add a worker to this swarm, run the following command:

    docker swarm join --token SWMTKN-1-4vnxn6cbq4gtsjjvaluucncc8m71aexe11dhbm40aoxfqnr7s3-bevjmv2qpklluuhm6ufrfoas2 192.168.65.3:2377

To add a manager to this swarm, run 'docker swarm join-token manager' and follow the instructions.

Ajeets-MacBook-Air:testenviron ajeetraina$ docker node ls
ID                            HOSTNAME                STATUS              AVAILABILITY        MANAGER STATUS
zfxiqqjpjmwbvhm1ahjwio3s7 *   linuxkit-025000000001   Ready               Active              Leader
Ajeets-MacBook-Air:testenviron ajeetraina$ docker stack deploy -c docker-compose.yml myapp3
Creating network myapp3_default
Creating service myapp3_db1
Creating service myapp3_web1
Ajeets-MacBook-Air:testenviron ajeetraina$ docker stack ls
NAME                SERVICES
myapp3              2

Switching the context from Minikube to docker-for-desktop

Ajeets-MacBook-Air:testenviron ajeetraina$ kubectl config get-contexts
CURRENT   NAME                          CLUSTER                      AUTHINFO             NAMESPACE
          docker-for-desktop            docker-for-desktop-cluster   docker-for-desktop
          gce                                                        cluster-admin
          kubernetes-admin@kubernetes   kubernetes                   kubernetes-admin
*         minikube                      minikube                     minikube

Ajeets-MacBook-Air:testenviron ajeetraina$ kubectl config use-context docker-for-desktop
Switched to context "docker-for-desktop".

Verifying through Pane UI

Open up whale icon under D4M and see if the context switched successfully.

Enabling Kubernetes

Go to whale icon > Click on Preference > Click on Kubernetes > Enable Kubernetes > Show Systems Containers

It will take few minutes to get Kubernetes up and running. Expect it to take long time if you are enabling kubernetes for the first time based on your internet speed.

Clone the Repository

$git clone https://github.com/ajeetraina/docker101

Change to the right location

$cd docker101/play-with-kubernetes/examples/stack-deploy-on-mac/

Example-1 : Demonstrating a Simple Web Application

Building the Web Application Stack

$docker stack deploy -c docker-stack1.yml myapp1

Verifying the Stack

$docker stack ls

Verifying using Kubectl

$kubectl get pods

Verifying if the web application is accessible

$curl localhost:8083

Cleaning up the Stack

$docker stack rm myapp`

Example:2 – Demonstrating ReplicaSet

Building the Web Application Stack

$docker stack deploy -c docker-stack2.yml myapp2

Verifying the Stack

$docker stack ls

Verifying using Kubectl

$kubectl get pods
Ajeets-MacBook-Air:testenviron ajeetraina$ kubectl get stacks
NAME      AGE
myapp2    22m
Ajeets-MacBook-Air:testenviron ajeetraina$ kubectl get pods
NAME                    READY     STATUS    RESTARTS   AGE
db1-d977d5f48-l6v9d     1/1       Running   0          22m
db1-d977d5f48-mpd25     1/1       Running   0          22m
web1-6886bb478f-s7mvz   1/1       Running   0          22m
web1-6886bb478f-wh824   1/1       Running   0          22m

Adding Context for Google Cloud

Pre-requisites:

  • Install google-cloud-sdk on macOS
  • Enable Google Cloud Engine API
  • Authenticate Your Google Cloud using gcloud auth

Creating GKE Cluster Node

Ajeets-MacBook-Air:~ ajeetraina$ gcloud container clusters create k8s-lab1 --disk-size 10 --zone asia-east1-a --machine-type n1-standard-2 --num-nodes 3 --scopes compute-rw
WARNING: The behavior of --scopes will change in a future gcloud release: service-control and service-management scopes will no longer be added to what is specified in --scopes. To use these scopes, add them explicitly to --scopes. To use the new behavior, set container/new_scopes_behavior property (gcloud config set container/new_scopes_behavior true).
WARNING: Starting in Kubernetes v1.10, new clusters will no longer get compute-rw and storage-ro scopes added to what is specified in --scopes (though the latter will remain included in the default --scopes). To use these scopes, add them explicitly to --scopes. To use the new behavior, set container/new_scopes_behavior property (gcloud config set container/new_scopes_behavior true).
Creating cluster k8s-lab1...done.
Created [https://container.googleapis.com/v1/projects/spheric-temple-187614/zones/asia-east1-a/clusters/k8s-lab1].
To inspect the contents of your cluster, go to: https://console.cloud.google.com/kubernetes/workload_/gcloud/asia-east1-a/k8s-lab1?project=spheric-temple-187614
kubeconfig entry generated for k8s-lab1.
NAME      LOCATION      MASTER_VERSION  MASTER_IP       MACHINE_TYPE   NODE_VERSION  NUM_NODES  STATUS
k8s-lab1  asia-east1-a  1.7.11-gke.1    35.201.215.156  n1-standard-2  1.7.11-gke.1  3          RUNNING

Verify it on Google Cloud

Cluster

Master version	
1.7.11-gke.1 Upgrade available
Endpoint	
35.201.215.156 Show credentials
Client certificate	
Enabled
Kubernetes alpha features	
Disabled
Total size	
3
Master zone	
...

Connecting to Your GKE Cluster

You can connect to your cluster via command-line or using a dashboard too.

Ajeets-MacBook-Air:~ ajeetraina$ gcloud container clusters get-credentials k8s-lab1 --zone asia-east1-a --project spheric-temple-187614

Fetching cluster endpoint and auth data. kubeconfig entry generated for k8s-lab1.

Listing the Nodes

Ajeets-MacBook-Air:~ ajeetraina$ kubectl get nodes
NAME                                      STATUS    ROLES     AGE       VERSION
gke-k8s-lab1-default-pool-042d2598-591g   Ready     <none>    7m        v1.7.11-gke.1
gke-k8s-lab1-default-pool-042d2598-c633   Ready     <none>    7m        v1.7.11-gke.1
gke-k8s-lab1-default-pool-042d2598-q603   Ready     <none>    7m        v1.7.11-gke.1

Did you find this blog helpful?  Feel free to share your experience. Get in touch @ajeetsraina.

If you are looking out for contribution/discussion, join me at Docker Community Slack Channel.

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2-minutes to Kubernetes Cluster on Docker for Mac 18.01 using Swarm CLI

Estimated Reading Time: 2 minutes

Docker for Mac 18.01.0 CE is available for the general public. It holds experimental Kubernetes release running on Linux Kernel 4.9.75, Docker Compose 1.180 and Docker Machine 0.13.0. It is available only under Edge Release. Please note that this feature is still NOT available under Stable Release branch. This release brought a major fixes around insecure registry, VPNKit port,  DNS timeout issues and many more which you can refer under Release Notes section.

[Updated – 29/01/2018 – Docker Inc. introduced Kubernetes context selector UI in the recent Docker for Mac 18.02 RC1 release. If you have Minikube already running on the same system, you can switch the context in between Minikube & docker for Mac flawlessly. Refer this for more information]

 

 

In my previous blog, I talked about how to build Kubernetes Cluster in 3 minutes using Kubectl tool which comes by default with this release. But what if you are a die-hard fan of   Docker Swarm CLI like me, here is the good news – You can now use Swarm CLI to bring up Kubernetes Cluster. Under this post, I will show you how Swarm CLI can be used to bring up Kubernetes cluster in just 2 minutes.

 

Pre-requisite:

  • Docker for Mac 18.01.0 CE Edge Release
  • Enable Kubernetes under Preference > Kubernetes Tab
  • Select Checkbox under Show System Container

A Quick 2-minutes ASCIINEMA video:

Here is 2-minutes video which shows how to get started from Zero to NGINX web server setup. It initiate with 0 pods, 0 external service and 0 deployments in Kubernetes terminology. Under this video, we will use the familiar docker stack CLI to bring up K8s cluster and then cleaning up in no seconds.

Liked the video? You can refer this link for detailed instructions and further examples.

As I dig deeper into Kubernetes architecture, below links might be useful for anyone who want to learn Kubernetes concepts in detail.

Getting Started with Kubernetes Concepts & Architecture

Building Kubernetes Dashboard on Docker for Mac in 1 min

Demystifying Kubernetes Namespace

Did you find this blog helpful?  Feel free to share your experience. Get in touch @ajeetsraina.

If you are looking out for contribution/discussion, join me at Docker Community Slack Channel.

 

 

 

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Docker For Mac 1.13.0 brings support for macOS Sierra, now runs ARM & AARCH64 based Docker containers

Estimated Reading Time: 6 minutes

Recently I purchased a brand new slim 13.3 inch Apple Mac Book  Air with an amazing 1.6GHz dual-core Intel Core i5 processor. Introducing Siri to newly re-branded macOS for the first time along with dozens of new features, it came by default running macOS 10.12.1 Sierra. macOS Sierra is the 13th major release of macOS(previously OS X)and successor of OS X El Capiton. ICYMI – Apple released macOS 10.12 Sierra open source Darwin code last November and can be accessed via https://opensource.apple.com/release/os-x-1012.html . One of the first thing I wanted to try out was to see how easy is it to bring Docker 1.13.0 up and running on this system. Trust me, it was an amazing experience. Under this blog post, I am going to share my experience with Docker 1.13.0 and what you really need to know about Docker for Mac on macOS Sierra.

16487451_10209801703852550_7429605017657917198_o

In case you are too new to Docker For Mac…

Last year during March time frame, Docker announced and released a native beta support for Mac and Windows, rightly termed as “Docker for Mac” & “Docker for Windows” respectively. They started with a closed beta & provided access to a couple of early adopters. During Dockercon 2016, they announced Final GA release for both the platforms.

Docker for Mac Vs. Docker Toolbox

difference_between_MacOSToolbox_D4M

 

Pre-Requisite:

  1. Docker for Mac only works on OS X 10.11 or newer macOS release.
  2. Apple Mac must be running 2010 or newer Mac system, with Intel HW support for MMU Virtualization.
  3. Docker for Mac require atleast 4GB of RAM to function smoothly.

Currently the installer comes in the form of 2 channels – stable and Beta. Under the stable channel, the installer is fully tested and comes with the latest GA version of Docker Engine. The Experimental feature is enabled by default.Under Beta channel, the installer provides the latest beta release of Docker for Mac with experimental features enabled by default.

Features enablement under Docker 1.13.0:

Features_1130

Getting Started with Docker Engine 1.13.0 on macOS Sierra

Installing Docker for Mac is one of fantastic experience I ever had installing any software. Just 3 simple steps:

  • Download Docker for Mac by clicking on this link and double-click Docker.dmg which opens up the installer.
  • Drag Moby the whale to the Application Folder as shown below:

Screen Shot 2017-01-29 at 2.52.53 PM

 

3.  Authorize Docker.app with your system password and double-click Docker.app to get started as shown below:

Screen Shot 2017-01-29 at 2.59.02 PM

Screen Shot 2017-01-29 at 2.59.12 PM

Screen Shot 2017-01-29 at 2.59.30 PM

 

Now this is really amazing. Docker for Mac comes with the default availability of docker-compose, docker-machine and experimental feature by default as shown below:

Screen Shot 2017-01-29 at 3.00.25 PM

  1. Verify the docker compose version:

bash-3.2# docker-compose version
docker-compose version 1.10.0, build 4bd6f1a
docker-py version: 2.0.1
CPython version: 2.7.12
OpenSSL version: OpenSSL 1.0.2j 26 Sep 2016

2. Verify the docker-machine version:

bash-3.2# docker-machine version

docker-machine version 0.9.0, build 15fd4c7

Kudos to Docker Engineers, the whale in the status bar is all you need to have a glimpse of overall Docker daemon running and easy way to configure Docker preferences & environment as per your need:

Screen Shot 2017-01-29 at 3.03.25 PM

Open the terminal and you can see that Docker for Mac runs on top of Alpine Linux v3.5, default storage driver as overlay2, Plugins support and many more.

Screen Shot 2017-01-29 at 6.04.50 PM

Multi-CPU Architecture Support(ARM, AARCH64 & PPC64le):

Apple Inc. added support for an ARM chip to the latest macOS Sierra 10.12 kernel. At the right time, Docker for Mac made binfmt_misc multi architecture support available,which means that now you can run containers for different Linux architectures, such as arm, aarch64 ppc64le and even s390x.

I couldn’t wait to test-drive few of Raspberry Pi ARM-based Docker images on my Mac Book Air. Here is how I tested few of ARM -based images:

bash-3.2# docker run -itd ajeetraina/centos7-arm /bin/bash

Unable to find image ‘ajeetraina/centos7-arm:latest’ locally

latest: Pulling from ajeetraina/centos7-arm

5584ea4c92c5: Pull complete

a3ed95caeb02: Pull complete

Digest: sha256:10989b1b7a3bdf826857ba5b3348956d495b9be1ced644a3aa7321cfbd705b04

Status: Downloaded newer image for ajeetraina/centos7-arm:latest

a719fb80aac98c2f2daddd7c5374bb2739d03285e74f7523cb0cc36258fc605e

bash-3.2# docker ps

CONTAINER ID        IMAGE                    COMMAND             CREATED             STATUS              PORTS               NAMES

a719fb80aac9        ajeetraina/centos7-arm   “/bin/bash”         2 minutes ago       Up 2 minutes                            suspicious_goldwasser

bash-3.2# docker exec -it a719f cat /etc/issue\S

Kernel \r on an \m

bash-3.2#

Please Note – The containers need to have the appropriate qemu binary inside the container to work, without qemu you can pull ARM-based Docker images but can’t run it.

Filesystem Sharing with OSXFS:

Docker for Mac brings a new shared filesystem, rightly called OSXFS  solution . OSXFS provides a close-to-native user experience for bind mounting OS X file system trees into Docker containers. It brings a number of unique capabilities as well as differences from a classical Linux file system. It does not use OSXFUSE and doesn’t run under, inside, or between OS X user space processes and the OS X kernel.

There are number of concerns around performance degradation around OSXFS and I think Docker team has rightly addressed it. It is worth reading  https://docs.docker.com/docker-for-mac/osxfs/#/performance-issues-solutions-and-roadmap to understand the problem statement and taking the right step. Said that, Docker team is continuously working to bring improvement under this space.

In the future blog post, I will talk about newer features and bug fixes which comes with Engine 1.13.0. Feel free to share if you like and reach out to me via @ajeetsraina(t).

 

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