Reputation: 3585
In this official document, it can run command in a yaml config file:
apiVersion: v1
kind: Pod
metadata:
name: hello-world
spec: # specification of the pod’s contents
restartPolicy: Never
containers:
- name: hello
image: "ubuntu:14.04"
env:
- name: MESSAGE
value: "hello world"
command: ["/bin/sh","-c"]
args: ["/bin/echo \"${MESSAGE}\""]
If I want to run more than one command, how to do?
Upvotes: 229
Views: 356779
Reputation: 94
Personally, I would do it like this because it's cleaner and I have see this a lot:
apiVersion: v1
kind: Pod
metadata:
name: almalinux
spec:
containers:
- name: almalinux
image: almalinux
command: ["/bin/sh", "-c"]
args:
- |
echo "Hello, World!"
echo "This is a test."
ip a
cat /etc/os-release
echo "This is how you can run multiple commands in a single container and keep it running."
tail -f /dev/null
The tail at the end keeps the pod running (it's quite useful).
the result bellow:
P.S.: I use k9s btw.
Upvotes: 3
Reputation: 1
migration-testing: - step: name: Run migration script: - pipe: atlassian/aws-eks-kubectl-run:2.2.1 variables: AWS_ACCESS_KEY_ID: $AWS_ACCESS_KEY_ID AWS_SECRET_ACCESS_KEY: $AWS_SECRET_ACCESS_KEY AWS_DEFAULT_REGION: $AWS_DEFAULT_REGION CLUSTER_NAME: $CLUSTER_NAME KUBECTL_COMMAND: exec KUBECTL_ARGS: - '-n' - 'test-namespace' - 'test-podname' - '-it' - '--' - '/bin/sh' - '-c' - 'npm run migrate' in place of test-podname I want to run another kubectl command to get current pod in namespace as podname is not fixed it takes some random numeric string after name provided in yaml file so that I dont have to worry about name of pod
Upvotes: 0
Reputation: 123
Here is another way to run multi line commands.
apiVersion: batch/v1
kind: Job
metadata:
name: multiline
spec:
template:
spec:
containers:
- command:
- /bin/bash
- -exc
- |
set +x
echo "running below scripts"
if [[ -f "if-condition.sh" ]]; then
echo "Running if success"
else
echo "Running if failed"
fi
name: ubuntu
image: ubuntu
restartPolicy: Never
backoffLimit: 1
Upvotes: 11
Reputation: 1158
Here is one more way to do it, with output logging.
apiVersion: v1
kind: Pod
metadata:
labels:
type: test
name: nginx
spec:
containers:
- image: nginx
name: nginx
volumeMounts:
- name: log-vol
mountPath: /var/mylog
command:
- /bin/sh
- -c
- >
i=0;
while [ $i -lt 100 ];
do
echo "hello $i";
echo "$i : $(date)" >> /var/mylog/1.log;
echo "$(date)" >> /var/mylog/2.log;
i=$((i+1));
sleep 1;
done
dnsPolicy: ClusterFirst
restartPolicy: Always
volumes:
- name: log-vol
emptyDir: {}
Upvotes: 10
Reputation: 26709
If you want to avoid concatenating all commands into a single command with ;
or &&
you can also get true multi-line scripts using a heredoc:
command:
- sh
- "-c"
- |
/bin/bash <<'EOF'
# Normal script content possible here
echo "Hello world"
ls -l
exit 123
EOF
This is handy for running existing bash scripts, but has the downside of requiring both an inner and an outer shell instance for setting up the heredoc.
Upvotes: 60
Reputation: 648
I am not sure if the question is still active but due to the fact that I did not find the solution in the above answers I decided to write it down.
I use the following approach:
readinessProbe:
exec:
command:
- sh
- -c
- |
command1
command2 && command3
I know my example is related to readinessProbe, livenessProbe, etc. but suspect the same case is for the container commands. This provides flexibility as it mirrors a standard script writing in Bash.
Upvotes: 29
Reputation: 347
Here is my successful run
apiVersion: v1
kind: Pod
metadata:
labels:
run: busybox
name: busybox
spec:
containers:
- command:
- /bin/sh
- -c
- |
echo "running below scripts"
i=0;
while true;
do
echo "$i: $(date)";
i=$((i+1));
sleep 1;
done
name: busybox
image: busybox
Upvotes: 13
Reputation: 210
IMHO the best option is to use YAML's native block scalars. Specifically in this case, the folded style block.
By invoking sh -c
you can pass arguments to your container as commands, but if you want to elegantly separate them with newlines, you'd want to use the folded style block, so that YAML will know to convert newlines to whitespaces, effectively concatenating the commands.
A full working example:
apiVersion: v1
kind: Pod
metadata:
name: myapp
labels:
app: myapp
spec:
containers:
- name: busy
image: busybox:1.28
command: ["/bin/sh", "-c"]
args:
- >
command_1 &&
command_2 &&
...
command_n
Upvotes: 14
Reputation: 135
Just to bring another possible option, secrets can be used as they are presented to the pod as volumes:
Secret example:
apiVersion: v1
kind: Secret
metadata:
name: secret-script
type: Opaque
data:
script_text: <<your script in b64>>
Yaml extract:
....
containers:
- name: container-name
image: image-name
command: ["/bin/bash", "/your_script.sh"]
volumeMounts:
- name: vsecret-script
mountPath: /your_script.sh
subPath: script_text
....
volumes:
- name: vsecret-script
secret:
secretName: secret-script
I know many will argue this is not what secrets must be used for, but it is an option.
Upvotes: 1
Reputation: 29601
My preference is to multiline the args, this is simplest and easiest to read. Also, the script can be changed without affecting the image, just need to restart the pod. For example, for a mysql dump, the container spec could be something like this:
containers:
- name: mysqldump
image: mysql
command: ["/bin/sh", "-c"]
args:
- echo starting;
ls -la /backups;
mysqldump --host=... -r /backups/file.sql db_name;
ls -la /backups;
echo done;
volumeMounts:
- ...
The reason this works is that yaml actually concatenates all the lines after the "-" into one, and sh runs one long string "echo starting; ls... ; echo done;".
Upvotes: 198
Reputation: 11303
If you're willing to use a Volume and a ConfigMap, you can mount ConfigMap data as a script, and then run that script:
---
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
This cleans up your pod spec a little and allows for more complex scripting.
$ kubectl logs my-pod
Do this
Do that
Upvotes: 78
Reputation: 7827
command: ["/bin/sh","-c"]
args: ["command one; command two && command three"]
Explanation: The command ["/bin/sh", "-c"]
says "run a shell, and execute the following instructions". The args are then passed as commands to the shell. In shell scripting a semicolon separates commands, and &&
conditionally runs the following command if the first succeed. In the above example, it always runs command one
followed by command two
, and only runs command three
if command two
succeeded.
Alternative: In many cases, some of the commands you want to run are probably setting up the final command to run. In this case, building your own Dockerfile is the way to go. Look at the RUN directive in particular.
Upvotes: 298