Override value in list with helm override file

Question

I want to override values between prod and dev deployments.

The default values look like:

apps:
  myapp:
    replicaCount: 2
    containers:
      - name: foo
        env:
          MODE: "dev"

I can override this in command line with:

--set apps.myapp.containers[0].env.mode="prod"

However I want to keep all the overrides in a file and run helm upgrade passing in an override file as well. Adding the override in the file like:

apps:
  myapp:
    containers[0]:
      env:
        MODE: "prod"

does NOT work. How do I override values inside a list?

Lusitania

Answer 1

It is weird to say the least.

This worked:

apps:
  myapp:
    containers[1]:
      env:
        MODE: "prod"

So the index for containers is 1 when overridden in a file, however 0 when done using command line:

--set apps.myapp.containers[0].env.mode="prod"

Lusitania

When using helm better try to achieve this while using a template in deployment.yaml and define these overrides in values.yaml – Misspend

Yes, these go in values.yaml. However we want override for values in values.yaml for different envs. We dont want to duplicate values.yaml for each env, so we have a base values.yaml + dev.yaml or prod.yaml with overrides that changes only relevant fields. – Lusitania

@Lusitania With helm version v3.14.2 your values.yaml example doesn't work. For me it creates a new key containers[1] and does not overwrites an item in the original containers list. And your command line example overwrites the whole containers, isn't it? So in example name: foo is gone. You used Helm 2? – Benge

I confirm what @Benge said, that this doesn't seem to work with helm v3.15 (in my case), neither the 0 nor the 1 index seems to work unfortunately. – Paralyze

Answer 2

It appears that changing just a subpath in an array while leaving the rest of the array untouched doesn't work anymore in Helm v3.15 (possibly already for much longer) - in contrast to the answer by @Barath.

The only way that works at this time is to use --set, i.e.

--set apps.myapp.containers[0].env.mode="prod"

Workaround using dict instead of list

A workraound is to convert the array to a dict where you use increasing integers as keys. Then you can use the override values.yaml again.

Replace this values.yaml:

apps:
  myapp:
    replicaCount: 2
    containers:
      - name: foo
        env:
          MODE: "dev"

With this values.yaml:

apps:
  myapp:
    replicaCount: 2
    containers:
      1:
        name: foo
        env:
          MODE: "dev"

Then you can override with:

apps:
  myapp:
    containers:
      1:
        env:
          MODE: "dev"

Paralyze