This article will describe how to run multiple commands on container startup phase in kubernetes. Kubernetes provides several ways to run multiple command for a container, such as command parameter in container spec, or provide an entry point shell. bellow is an example for demonstrate how to run multiple commands in kubernetes.
Using command parameter
apiVersion: v1
kind: Pod
metadata:
labels:
run: busybox
name: busybox
spec:
containers:
- command:
- /bin/sh
- -c
- |
echo "running below scripts"
i=0;
while true;
do
echo "$i: $(date)";
i=$((i+1));
sleep 1;
done
name: busybox
image: busybox
Also, you can use command and args parameters, for better readablity, yaml scalar block(>-) is prefered:
apiVersion: v1
kind: Pod
metadata:
name: hello-world
spec: # specification of the pod’s contents
restartPolicy: Never
containers:
- name: hello
image: "ubuntu:14.04"
command: ["/bin/sh"]
args:
- -c
- >-
command1 arg1 arg2 &&
command2 arg3 &&
command3 arg4
The third way, you can put your commands in a bash shell as a configmap, and mount that file in container,
---
apiVersion: v1
kind: ConfigMap
metadata:
name: my-configmap
data:
entrypoint.sh: |-
#!/bin/bash
echo "Do this"
echo "Do that"
---
apiVersion: v1
kind: Pod
metadata:
name: my-pod
spec:
containers:
- name: my-container
image: "ubuntu:14.04"
command:
- /bin/entrypoint.sh
volumeMounts:
- name: configmap-volume
mountPath: /bin/entrypoint.sh
readOnly: true
subPath: entrypoint.sh
volumes:
- name: configmap-volume
configMap:
defaultMode: 0700
name: my-configmap