Allow replacing stanley with an alternate user

[cognifloyd]

In my environment, the security team has strict requirements about the naming of service user accounts, so I can't us stanley.

In the st2.config value, I can change that user, and the ssh key as shown in https://github.com/StackStorm/st2/blob/master/conf/st2.conf.sample#L317-L321

[system_user]
# SSH private key for the system user.
ssh_key_file = /home/notstanley/.ssh/stanley_rsa
# Default system user.
user = notstanley

Then, I can use a custom st2actionrunner image that adds the notstanley account and home directory.
But, the name stanley is hard-coded in a couple of places. This is for the st2actionrunner pod, but the same applies to the st2client pod as well.
https://github.com/StackStorm/stackstorm-ha/blob/aabf3dcb201a86d5ddf6717cffc9dd76267181b5/templates/deployments.yaml#L1033-L1035
https://github.com/StackStorm/stackstorm-ha/blob/aabf3dcb201a86d5ddf6717cffc9dd76267181b5/templates/deployments.yaml#L1070-L1073

I think I would add new options in values:

st2:
  # This mirrors the [system_user] section of st2.conf, but makes the values available for helm templating.
  # If you change the user, you must provide a customized st2actionrunner image that includes your user.
  system_user:
    user: stanley
    # if ssh_key_file is not defined, default is: /home/$system_user/.ssh/stanley_rsa
    #ssh_key_file:

Then, in st2-config configmap (in st2.docker.conf), add:

    {{- if index .Values "st2" "system_user" }}
    [system_user]
    user = {{ .Values.st2.system_user.user | default "stanley" }}
    {{- if index .Values "st2" "system_user" "ssh_key_file }}
    ssh_key_file = {{ .Values.st2.system_user.ssh_key_file }}
    {{- else }}
    ssh_key_file = /home/{{ .Values.st2.system_user }}/.ssh/stanley_rsa
    {{- end }}
    {{- end }}

With similar changes to templates/deployments.yaml for the ssh key mount paths.

I'm working on fixing the ssh key file permissions in #203 (to fix #84) so it would be easy to include this change in there, or I can wait till after that (or similar) is merged and add the configuration on top of it in a separate PR.

[arm4b]

👍
I remember at least one request from the community about customizing the default user name.

[cognifloyd]

Shall I add this to #206?

[arm4b]

I think it's better to keep them separated for the better history and faster iteration. Eg merging #206 first.

[cognifloyd]

Once #206 #219 is merged, I'll submit a PR with this commit to allow an alternate system_user:
cognifloyd/stackstorm-k8s@lifecycle-hooks...configurable-stanley

[cognifloyd]

This is implemented in #220 - but that depends on #219 being merged first.