panchalhimself
Multicontainer Pods in Kubernetes
20 June 2023
Multiple containers inside a single kubernetes pod.
What is the use case of multi containers in a single pod ?
Well for tightly coupled applications and sidecar setup this is an efficient setup.
Sometimes you might need another container to process things from the main container kind of like a helper container.
mounted volumes to the pod can be used by all the containers in the pod.
network and storage are essentially shared among containers.
containers within the pod can communicate with each other without explicit port exposure.
let us create a simple template first using following command:
kubectl run multicontainer-pod --image=nginx --dry-run=client -o yaml > multicontianerpod.yaml
modify the multicontainerpod.yaml file as follows:-
apiVersion: v1
kind: Pod
metadata:
creationTimestamp: null
labels:
run: multicontainer-pod
name: multicontainer-pod
spec:
containers:
- image: nginx
name: multicontainer-pod-nginx
resources: {}
- image: redis
name: multicontainer-pod-redis
resources: {}
dnsPolicy: ClusterFirst
restartPolicy: Always
status: {}
Example: where one pod prints something to a file another reads it.
multi.yaml
apiVersion: v1
kind: Pod
metadata:
creationTimestamp: null
labels:
run: multi
name: multi
spec:
containers:
- image: busybox
name: bb1
command: ['sh','-c','while true; do echo hello > /mountpath/Hello; sleep 5; done']
volumeMounts:
- name: myvolume
mountPath: /mountpath
- image: busybox
name: bb2
command: ['sh','-c','tail -f /mountpath/Hello;']
volumeMounts:
- name: myvolume
mountPath: /mountpath
volumes:
- name: myvolume
dnsPolicy: ClusterFirst
restartPolicy: Always
status: {}
output:
