Kubernetes has become the de facto standard for container orchestration, providing a powerful platform for deploying, managing, and scaling containerised applications. As a developer, understanding Kubernetes best practices is crucial to ensure smooth deployments, efficient operations, and enhanced security. In this blog post, we will explore 15 Kubernetes best practices that every developer should know, along with code snippets and YAML examples.
1. Use Kubernetes Native Resources
Kubernetes provides a rich set of native resources, such as pods, deployments, services, and volumes, for managing containerized applications. It’s important to use these native resources instead of creating custom scripts or workarounds. Native resources are designed to work seamlessly with Kubernetes and provide better manageability, scalability, and security.
For example, here’s a YAML example of a simple pod definition:
apiVersion: v1
kind: Pod
metadata:
name: my-pod
spec:
containers:
- name: my-container
image: my-image:tag
ports:
- containerPort: 80
2. Follow the Principle of Single Responsibility
Each containerized application should have a single responsibility, meaning it should perform only one task or function. Avoid bundling multiple services or applications into a single container, as it can make management and scaling more complex. Instead, use separate containers or pods for each component of your application.
Here’s an example of a pod definition for a multi-container application with separate containers for the frontend and backend:
apiVersion: v1
kind: Pod
metadata:
name: my-app
spec:
containers:
- name: frontend
image: frontend-image:tag
ports:
- containerPort: 80
- name: backend
image: backend-image:tag
ports:
- containerPort: 8080
3. Define Resource Limits and Requests
Resource limits and requests allow you to allocate the appropriate amount of resources to your containers, preventing resource contention and ensuring optimal performance. Define resource limits and requests based on the requirements of your application and the resources available in your cluster.
Here’s an example of a pod definition with resource limits and requests:
apiVersion: v1
kind: Pod
metadata:
name: my-pod
spec:
containers:
- name: my-container
image: my-image:tag
resources:
limits:
cpu: "1"
memory: "1Gi"
requests:
cpu: "0.5"
memory: "500Mi"
4. Use Labels and Annotations
Labels and annotations allow you to attach metadata to your Kubernetes objects, providing a way to organize, filter, and manage your resources. Use labels to tag your resources with meaningful information, such as app name, environment, version, etc. Use annotations to add additional information, such as configuration details or documentation links.
Here’s an example of a pod definition with labels and annotations:
apiVersion: v1
kind: Pod
metadata:
name: my-pod
labels:
app: my-app
environment: production
annotations:
config: "https://my-config.com"
spec:
containers:
- name: my-container
image: my-image:tag
5. Use ReplicaSets or Deployments for Scalability
To ensure high availability and scalability, use ReplicaSets or Deployments instead of directly creating pods. ReplicaSets and Deployments allow you to define the desired number of replicas for your application and automatically handle scaling up or down based on demand.
Here’s an example of a Deployment definition for scaling an application:
apiVersion: apps/v1
kind: Deployment
metadata:
name: my-deployment
spec:
replicas: 3
selector:
matchLabels:
app: my-app
template:
metadata:
labels:
app: my-app
spec:
containers:
- name: my-container
image: my-image:tag
ports:
- containerPort: 80
6. Use Namespaces for Resource Isolation
Namespaces allow you to create logical partitions within a cluster, providing resource isolation and access control. Use namespaces to group resources based on projects, teams, or environments, and avoid using the default namespace for your applications. This helps prevent resource name clashes and provides better organization and security.
Here’s an example of a pod definition with a namespace:
apiVersion: v1
kind: Pod
metadata:
name: my-pod
namespace: my-namespace
spec:
containers:
- name: my-container
image: my-image:tag
ports:
- containerPort: 80
7. Use RBAC for Access Control
Role-Based Access Control (RBAC) allows you to define fine-grained access control rules for users and groups within a Kubernetes cluster. Use RBAC to restrict access to sensitive resources and operations, and grant only the necessary permissions to users and groups. Avoid using the default cluster-admin role for regular users or services to reduce the risk of unauthorized access.
Here’s an example of an RBAC role definition:
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
name: my-role
rules:
- apiGroups: [""]
resources: ["pods"]
verbs: ["get", "list", "create", "update", "delete"]
8. Use Secrets for Sensitive Data
Avoid storing sensitive data, such as passwords, API keys, or certificates, in plain text in your container images or Kubernetes manifests. Instead, use Kubernetes Secrets to store sensitive data securely and reference them in your application manifests. Secrets are encrypted and can be managed independently, providing a more secure way to handle sensitive data.
Here’s an example of a secret definition:
apiVersion: v1
kind: Secret
metadata:
name: my-secret
type: Opaque
data:
username: dXNlcm5hbWU=
password: cGFzc3dvcmQ=
9. Use Health Checks
Health checks allow you to ensure that your containers are running correctly and ready to serve traffic. Use readiness probes to check if your containers are ready to receive traffic and liveness probes to check if your containers are still running correctly. Proper use of health checks helps Kubernetes detect and recover from failures, ensuring high availability of your applications.
Here’s an example of a pod definition with health checks:
apiVersion: v1
kind: Pod
metadata:
name: my-pod
spec:
containers:
- name: my-container
image: my-image:tag
ports:
- containerPort: 80
readinessProbe:
httpGet:
path: /health
port: 80
initialDelaySeconds: 5
periodSeconds: 10
livenessProbe:
httpGet:
path: /health
port: 80
initialDelaySeconds: 10
periodSeconds: 30
10. Use Rolling Updates for Deployment
When updating your application, use rolling updates for Deployments to ensure zero downtime and smooth updates. Rolling updates allow you to update your application gradually, one replica at a time, while maintaining the desired number of replicas running at all times. This helps minimize disruptions and ensures that your application remains available during updates.
Here’s an example of a Deployment definition with rolling updates:
apiVersion: apps/v1
kind: Deployment
metadata:
name: my-deployment
spec:
replicas: 3
selector:
matchLabels:
app: my-app
template:
metadata:
labels:
app: my-app
spec:
containers:
- name: my-container
image: my-image:tag
ports:
- containerPort: 80
strategy:
type: RollingUpdate
rollingUpdate:
maxUnavailable: 1
maxSurge: 1
11. Use Resource Limits and Requests
Define resource limits and requests for your containers to ensure fair resource allocation and prevent resource contention. Resource limits specify the maximum amount of resources a container can use, while resource requests specify the amount of resources a container requires to run. Properly setting resource limits and requests helps prevent resource exhaustion and ensures optimal performance of your applications.
Here’s an example of a pod definition with resource limits and requests:
apiVersion: v1
kind: Pod
metadata:
name: my-pod
spec:
containers:
- name: my-container
image: my-image:tag
ports:
- containerPort: 80
resources:
limits:
cpu: "1"
memory: "256Mi"
requests:
cpu: "0.5"
memory: "128Mi"
12. Use Persistent Volumes and Persistent Volume Claims
Use Persistent Volumes (PVs) and Persistent Volume Claims (PVCs) to store data persistently in your cluster. PVs are cluster-wide resources that represent physical storage resources, while PVCs are used to request a specific amount of storage from a PV. By using PVs and PVCs, you can ensure that your application data is preserved even if the container or pod is rescheduled or rescheduled to a different node.
Here’s an example of a Persistent Volume Claim definition:
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: my-pvc
spec:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
13. Use Labels and Annotations for Metadata
Labels and annotations are used to attach metadata to Kubernetes objects, such as pods, services, and volumes. Labels are used to identify and filter objects, while annotations are used to attach arbitrary metadata to objects. Use labels and annotations to provide meaningful metadata to your objects, such as application names, version numbers, or environment names, which can help with filtering, querying, and debugging.
Here’s an example of a pod definition with labels and annotations:
apiVersion: v1
kind: Pod
metadata:
name: my-pod
labels:
app: my-app
annotations:
version: v1.0.0
spec:
containers:
- name: my-container
image: my-image:tag
ports:
- containerPort: 80
14. Monitor and Observe Your Cluster
Monitoring and observing your Kubernetes cluster is crucial to ensuring the health and performance of your applications. Use tools like Prometheus, Grafana, or Kubernetes-native monitoring solutions like Kubernetes Metrics Server to collect and analyze metrics from your cluster, such as CPU usage, memory usage, and network traffic. Set up alerts and notifications to proactively monitor your cluster and receive notifications when any issues arise.
Here’s an example of using Prometheus and Grafana for monitoring your cluster:
apiVersion: monitoring.coreos.com/v1
kind: ServiceMonitor
metadata:
name: my-service-monitor
spec:
selector:
matchLabels:
app: my-app
endpoints:
- port: metrics
path: /metrics
interval: 30s
15. Use RBAC for Access Control
Implement Role-Based Access Control (RBAC) to control access to your Kubernetes resources and ensure that only authorized users have permissions to perform operations on your cluster. Use ClusterRoles and ClusterRoleBindings to define roles and bindings that grant specific permissions to users, groups, or service accounts. Restrict the use of overly permissive roles and follow the principle of least privilege to minimize security risks.
Here’s an example of a ClusterRole and ClusterRoleBinding definition:
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
name: my-cluster-role
rules:
- apiGroups: ["", "extensions", "apps"]
resources: ["pods", "deployments"]
verbs: ["get", "list", "watch", "create", "update", "delete"]
- apiGroups: [""]
resources: ["services"]
verbs: ["get", "list", "watch"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
name: my-cluster-role-binding
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: my-cluster-role
subjects:
- kind: User
name: john.doe
apiGroup: rbac.authorization.k8s.io
Conclusion
Kubernetes is a powerful and complex container orchestration platform that requires proper configuration and management to ensure the smooth operation of your applications. By following these 15 Kubernetes best practices, you can optimize the performance, reliability, and security of your Kubernetes clusters, and streamline your application deployment and management processes.
Remember to always follow the Kubernetes documentation and stay updated with the latest best practices and security recommendations. Regularly review and audit your Kubernetes configurations to identify and address any potential security risks or performance bottlenecks. Additionally, leverage monitoring and observability tools to proactively monitor your cluster and promptly respond to any issues that may arise.
By adhering to these best practices, you can ensure that your Kubernetes deployments are efficient, reliable, and secure, and your applications run smoothly in a production environment. Happy Kubernetes coding!
