Estimated Reading Time: 5 minutes

Raspberry Pi 3 Model B is the first 64 bit version and the third generation Pi box which runs on 1.2GHz 64 bit quad-core ARMv8 CPU.(Broadcom BCM2837 A53 ARM processor). Despite its processor upgrade, there wasn’t an official 64-bit OS available for it till the first week of Jan 2017. Kudos to SUSE Team, they came up providing first commercial enterprise Linux distribution optimized for ARM AARCH64 servers. This is definitely a BIG news. Reason –  To build a solution to meet specific market needs while maintaining a common code base. Enterprise vendors & customers demanding workload-optimized server platforms can now radically expand it for their modern data centers.

In the last couple of months, Docker enthusiasts have been working hard to get Docker running on ARM 32bit systems (like Raspberry Pi). With Docker Engine 1.12.1, a FIRST ARM Debian package was officially made available by Docker Inc. which happened late last year. This year, SUSE Team did a great job in bringing capabilities of SUSE Linux(a.k.a SLES for ARM) to the ARM AArch64 hardware platform. This is BIG news for Docker community too as more innovation and development is expected to grow building containers which will run across the  AARCH64 platform.

Under this blog, I am going to test drive Docker 1.12.3 on first 64-bit ARM Open SUSE distribution running on Raspberry Pi 3 box.

Hardware:

1. Raspberry Pi 3 ( You can order it from Amazon in case you are in India for $35)
2. Micro-SD card reader ( I got it from here )
3. Any Windows or Linux Desktop or Laptop
4. HDMI cable ( I used the HDMI cable of my plasma TV)
5. Internet Connectivity(WiFi/Broadband/Tethering using Mobile) – to download Docker 1.12.3 package
6. Keyboard & mouse connected to Pi’s USB ports

                                                                                            Source~http://www.rlocman.ru/i/Image/2016/02/29/RaspberryPi_3_1.jpg

Software:

1. SD-Formatter – to format microSD card
2. Rufus(in case you have Windows OS running on your laptop) – to burn OpenSUSE Leap 42.2 ARM XZ format directly into microSD card.(No need to extract XZ using any tool)

Steps:

1. Format the microSD card using SD Formatter as shown below:

2. Download OpenSUSE Leap 42.2 ARM  OS from here and use Win32 imager(in case you are on Windows OS  running on your laptop) to burn it on microSD card.

3. Insert the microSD card into your Pi box. Now connect the HDMI cable  from one end of Pi’s HDMI slot to your TV or display unit and mobile charger(recommended 5.1V@1.5A) as shown:

4.You will see the fancy GUI coming up on your display:

5. To enable VNC, run the below command:

linux:~ # zypper install xorg-x11-Xvnc

linux:~# vncserver

Installing Docker 1.12.3 on first 64-bit ARM OpenSUSE

6. Run the below command:

$curl -sSLk https://get.docker.com/ | sh

7. Verify the docker version:

8. Let us try searching for Docker images present in Dockerhub based on aarch64:

Please be aware that the usual Docker containers are not going to work for this architecture. You need to pick up AARCH64 bit Docker images to run containers.

linux:~ # docker run busybox
Unable to find image ‘busybox:latest’ locally
latest: Pulling from library/busybox

557a0c95bfcd: Pull complete
Digest: sha256:ae007bdb45fc0d56e3d705b97640ac24844bcc9ce4c8b8493f216a57ab6af0d5
Status: Downloaded newer image for busybox:latest
panic: standard_init_linux.go:175: exec user process caused “exec format error” [recovered]
panic: standard_init_linux.go:175: exec user process caused “exec format error”

goroutine 1 [running, locked to thread]:
panic(0x7bcaa0, 0x4820161ce0)

Installing Docker 1.13 on 64-bit ARM OS:

Docker doesn’t officially support AARCH64 system. You can’t use one-liner command to install Engine 1.13 as shown below:

If you really want to try 1.13, the easier way is downloading it from the below link:

Installing docker-compose

linux:~ # zypper install python-pip

linux:~ # pip install docker-compose

Tested docker-compose v2.0 functionality by bringing up microservices and it went fine.

Testing Swarm Mode:

linux:~/collabnix # docker service ls
ID            NAME        REPLICAS  IMAGE          COMMAND
0x7dlmr4pjm7  backend-db  1/1       aarch64/redis

linux:~/collabnix # docker service ps backend-db
ID                         NAME          IMAGE          NODE   DESIRED STATE  CURRENT STATE                 ERROR
7jmkwcbzq8wix3umfkcqc92rw  backend-db.1  aarch64/redis  linux  Running        Preparing about a minute ago

 

Estimated Reading Time: 5 minutes

Why should I deploy Docker to IoT devices? What are the use cases of running containers inside the IoT device like Raspberry Pi? Is Docker on IoT devices just for hobbyists? – To answer all these burning queries, I just thought of sharing one of the most interesting use case inside the datacentre lab which will surely attract infinite number of possibilities and implementation with Docker containers.

Imagine a small credit card size server sitting just below your ToR (Top of the Rack) switch, consuming very low power ( similar to your mobile device), not bound by wired Ethernet( Wi-Fi Direct, ZigBee) for mobile access and control, connected to ToR switch to discover the overall hardware, software managed and deployed through air, no monitor, keyboard and mouse intervention required – just boots up, discovers all your servers(rack/blades), storage(FC/iSCSI), Converged Infrastructure and network devices automatically and ready to monitor all of these datacentre equipment on the mobile & Web UI . Sounds interesting?? What if I say I have a single DOCKER container running inside this credit card size device handling all these functionality? Sounds crazy? Let me share the recent experience I had prototyping and designing this solution.

Why should I deploy Docker to IoT devices?

Docker is an open platform to build, ship and run your application anywhere: in your laptop, workstation, server, in a private or public cloud, within a local VM, or on physical hardware including IoT devices. Docker is very lightweight and this is what attracts developers who can apply to rapidly develop, test, deploy, and update IoT applications at scale. With very less disk, low memory resources and almost zero run-time overhead, deploying Docker on IoT devices like Raspberry Pi is considered a feasible solution.

Example: Let’s consider NagiosPi – a lightweight, feature rich & fully configured Server Monitoring Distro for the Raspberry Pi. To setup NagiosPi, one need to download the image and flash to SD card. Then, you need to boot through this SD card to use this tool.  Why not just pull Nagios Docker image from Dockerhub and run it? I am sure you will save a lot rather than flashing your entire SD card and loosing the underlying OS.In short,  if you run containers directly on your device, you can avoid having to constantly flash your device or overwrite the entire firmware. Instead you can build new images, pull them and run them within the host OS on the device.

I built the first Nagios container for ARM device few days back and pushed it to Dockerhub. You can refer https://github.com/ajeetraina/nagios-centos-arm

Just run the single Docker run command and Nagios is ready which you can easily see on the WebUI through http://<IP>/nagios.

Building Out-of-Band Monitoring Tool using Docker

Nagios is a free and open source monitoring and alerting service for servers, switches,applications and services. It basically collects the statistics of your server using agents like nrpe, check_mk or using SNMP and sends the alert if the metric value is above the predefined threshold. One of the implementation  of such tool is most of the time it’s configured as in-band connectivity which means software that is installed on the remote system being managed and only works after the operating system has been booted. If you want to monitor hundreds and thousands of such servers, you need to ensure that the agent plugin should be running on each nodes.

What if I want to monitor the physical health of servers, storage and network switches? Say, you are running a huge data center for High Performance Cluster Computing (HPCC) kind of workloads and you want to make sure that the health of your servers is all fine. In case, any of the servers goes bad in terms of memory DIMMs, the in-band monitoring system needs lots of complex configuration to be carried out to meet the right implementation. Out-of-band(OOB) monitoring system finally comes for a rescue. OOB uses a dedicated channel for managing the hardware devices like network devices. This allows the network operator to establish trust boundaries in accessing the management function to apply it to network resources.

How about using the tiny Raspberry Pi which can do OOB monitoring for the entire infrastructure?  Why do I need to setup a big system if this small credit card size can do what I really need? I spent considerable amount of time to come up with a viable solution and finally initiated building Out of Band monitoring tool . This was purely based on one of my previous work https://hub.docker.com/r/ajeetraina/dell-oob-monitoring/  which I built for X86 infrastructure.

https://www.youtube.com/watch?v=lpaeTepVETg&feature=youtu.be

How does it work?

All you need is list out all the IP addresses in one simple text file and run the below command:

Step-1: List out the IP addresses of Chassis, Storage devices, iDRAC IPs etc. in a plain text file using notepad or vim editor. Example: I saved the file called “ips” under /IP folder in the Docker Host machine as:

File: /IP/ips

100.94.214.181
100.94.214.178
100.94.214.190
100.94.214.210
……
……

Step:2: Execute the below command to start the container:

$sudo docker run -dit  --net=host -v /IP:/IP ajeetraina/dell-oob-monitoring:v1.0

Step3: Execute the following command to add the list of Dell servers, storage and chassis in a single shot:

$sudo docker exec -it <container-id> sh discover

Open up your browser http://<dockerhost>/nagios to see all the listed servers, storage and chassis added automatically to Nagios console and ready to be monitored.

Sounds Interesting?? Though I have tested this container internally and it just works out of box, I am still working on making it more lightweight. Stay tuned !

In the future post, I am going to talk more use cases of Docker on Raspberry Pi box. Keep Reading !

Estimated Reading Time: 5 minutes

In the previous post, I showed how to get Docker 1.12.1 up and running on Raspberry Pi3 in just 5 minutes. Under 1.12.1 release, Docker Inc. provided a FIRST ARM debian package which can be installed using a single curl command. It works great and there has been numerous Ubuntu, Alpine and Debian based ARM Docker images been built and pushed out to Dockerhub. If you are CentOS/Red Hat user, you might be interested in building CentOS based ARM images on top of Raspberry Pi. As of today, there is NO CentOS based Docker image available for ARM architecture under Dockerhub. I had few of X86 based legacy application which only runs on CentOS based system and hence decided to build one of my own for ARM. It is important to note that X86 based Docker image is not going to work on Raspberry Pi box.

This step-by-step guide will help you to build the CentOS 7.2 ARM Docker Image.

Step-1: Download the CentOS 7 specific ARM image from the official CentOS website.

root@raspberry5:/# wget http://mirror.centos.org/altarch/7/isos/armhfp/CentOS-Userland-7-armv7hl-Minimal-1603-RaspberryPi3.img.xz

 

Luckily, I found that CentOS community has ARM images availability for all popular vendors such as  BananaPi, CubieTruck, Pi2 and Pi3. I picked up the right one which will work for my Pi 3 box.

Step-2:  Format your microSD card in case you have old Raspbian OS using SD Formatter(Refer here)

Step-3: Use Win32 disk imager to burn it directly into microSD card.

Step-4: Insert microSD card into microSD slot of your Pi 3 box and power it on.

The default username & password is root/centos. This is a minimal CentOS 7 ARM image and hence don’t expect GUI out of this image. By default, WiFi is not enabled. Refer README file under the root directory to get WiFi working. I had a small cable to connect to my router and the network just worked out of the box. I installed vncserver using YUM and could connect to the Pi 3 box without any issue.

 

Step-5:  Ensure that you run “yum update” to get the latest ARM packages for CentOS 7

Step-6: By default, 2GB is the size allocated for / root partition. Follow the below step for expanding it to utilize the full 12GB of the space.

$sudo git clone https://github.com/ctyler/rootfs-resize

$sudo touch /.rootfs-repartition

$sudo systemctl reboot

Step-7:Now configure the YUM repo to pick up the required packages for Docker. I did a little tweaking here by including RPMs available from foreign unofficial repository.

Ensure that you run ‘yum update’ command again to get the latest packages for Docker packages.

Step-8: Run the below command to get the required number of packages to be installed:

$sudo yum install lxc bridge-utils device-mapper device-mapper-libs \

libsqlite3x docker-registry docker-storage-setup docker-io

Ensure that you run the below command to start the docker service:

$sudo systemctl start docker.service

Step-9: Verify if Docker is installed or not on Raspberry Pi 3 through ‘docker version’ utility:

You can get the detailed information about Docker  through ‘docker info’ command:

Yipee ! You got Docker installed on your CentOS base image on Raspberry Pi 3 box for the first time.

Let’s quickly try to pull few of the container from Dockerhub.

One can quickly start a container as shown below:

Let’s build up the first Docker ARM image for Dockerhub so that everyone can use it to build application on RPM based ARM container.

Building a container is a simplified process. All you need is a script which you can pull from this github link.Just run the below command to get CentOS 7.2 up and tested automatically:

[root@centos-rpi3 contrib]# sh mkimage-yum.sh -y /etc/yum.repos.d/CentOS-Base.repo centos7

As you see the above command, I have used CentOS-Base.repo as a source repository to create Docker image successfully. Hence, this image is just 210 MB in size. I am planning to shrink it to lower size soon so that it comes up better than before.

Feel free to pull and try out the first CentOS 7.2 container in your Pi box:

$sudo docker run -i -t –rm centos7:7.2 /bin/bash -c ‘echo success’
success

This is just awesome ! Now I have a platform to build monitoring tool on top of very tiny Raspberry Pi and this is going to be real fun. Will keep you all posted on the latest findings. Till then, keep Reading !