Start kubernetes container with specific command

Question

Using fleet I can specify a command to be run inside the container when it is started. It seems like this should be easily possible with Kubernetes as well, but I can't seem to find anything that says how. It seems like you have to create the container specifically to launch with a certain command.

Having a general purpose container and launching it with different arguments is far simpler than creating many different containers for specific cases, or setting and getting environment variables.

Is it possible to specify the command a kubernetes pod runs within the Docker image at startup?

Answer 1

I spend 45 minutes looking for this. Then I post a question about it and find the solution 9 minutes later.

There is an hint at what I wanted inside the Cassandra example. The command line below the image:

id: cassandra kind: Pod apiVersion: v1beta1 desiredState:   manifest:     version: v1beta1     id: cassandra     containers:       - name: cassandra         image: kubernetes/cassandra         command:           - /run.sh         cpu: 1000         ports:           - name: cql             containerPort: 9042           - name: thrift             containerPort: 9160         env:           - key: MAX_HEAP_SIZE             value: 512M           - key: HEAP_NEWSIZE             value: 100M labels:   name: cassandra 

Despite finding the solution, it would be nice if there was somewhere obvious in the Kubernetes project where I could see all of the possible options for the various configuration files (pod, service, replication controller).

Answer 2

for those looking to use a command with parameters, you need to provide an array

for example

command: [ "bin/bash", "-c", "mycommand" ] 

or also

command:   - "bin/bash"   - "-c"   - "mycommand"