feat: easier way to share configuration across helmfiles (#522)

This basically allows to define both `releases` and `helmfiles` within a helmfile.yaml, so that you can start using sub-helmfiles easily, by extracting only reused releases. Resolves #445
2026-10-10 14:46:15 +02:00 · 2019-03-31 22:51:06 +09:00
parent 283dac1531
commit 14a392666e
3 changed files with 175 additions and 13 deletions
@@ -0,0 +1,160 @@
+# Shared Configuration Across Teams
+
+Assume you have a two or more teams, each works for a different internal or external service, like:
+
+- Product 1
+- Product 2
+- Observability
+
+The simplest `helmfile.yaml` that declares the whole cluster that is composed of the three services would look like the below:
+
+```yaml
+releases:
+- name: product1-api
+  chart: product1-charts/api
+  # snip
+- name: product1-web
+  chart: product1-charts/web
+  # snip
+- name: product2-api
+  chart: saas-charts/api
+  # snip
+- name: product2-web
+  chart: product2-charts/web
+  # snip
+- name: observability-prometheus-operator
+  chart: stable/prometheus-operator
+  # snip
+- name: observability-process-exporter
+  chart: stable/prometheus-operator
+  # snip
+```
+
+This works, but what if you wanted to a separate cluster per service to achieve smaller blast radius?
+
+Let's start by creating a `helmfile.yaml` for each service.
+
+`product1/helmfile.yaml`:
+
+```yaml
+releases:
+- name: product1-api
+  chart: product1-charts/api
+  # snip
+- name: product1-web
+  chart: product1-charts/web
+  # snip
+- name: observability-prometheus-operator
+  chart: stable/prometheus-operator
+  # snip
+- name: observability-process-exporter
+  chart: stable/prometheus-operator
+  # snip
+```
+
+`product2/helmfile.yaml`:
+
+```yaml
+releases:
+- name: product2-api
+  chart: product2-charts/api
+  # snip
+- name: product2-web
+  chart: product2-charts/web
+  # snip
+- name: observability-prometheus-operator
+  chart: stable/prometheus-operator
+  # snip
+- name: observability-process-exporter
+  chart: stable/prometheus-operator
+  # snip
+```
+
+You will (of course!) notice this isn't DRY.
+
+To remove the duplication of observability stack between the two helmfiles, create a "sub-helmfile" for the observability stack.
+
+`observability/helmfile.yaml`:
+
+```yaml
+- name: observability-prometheus-operator
+  chart: stable/prometheus-operator
+  # snip
+- name: observability-process-exporter
+  chart: stable/prometheus-operator
+  # snip
+```
+
+As you might have imagined, the observability helmfile can be reused from the two product helmfiles by declaring `helmfiles`.
+
+`product1/helmfile.yaml`:
+
+```yaml
+helmfiles:
+- ../observability/helmfile.yaml
+
+releases:
+- name: product1-api
+  chart: product1-charts/api
+  # snip
+- name: product1-web
+  chart: product1-charts/web
+  # snip
+```
+
+`product2/helmfile.yaml`:
+
+```yaml
+helmfiles:
+- ../observability/helmfile.yaml
+
+releases:
+- name: product2-api
+  chart: product2-charts/api
+  # snip
+- name: product2-web
+  chart: product2-charts/web
+  # snip
+```
+
+## Using sub-helmfile as a template
+
+You can go even further by generalizing the product related releases as a pair of `api` and `web`:
+
+`product/helmfile.yaml`:
+
+```yaml
+releases:
+- name: product{{ env "PRODUCT_ID" }}-api
+  chart: product{{ env "PRODUCT_ID" }}-charts/api
+  # snip
+- name: product{{ env "PRODUCT_ID" }}-web
+  chart: product{{ env "PRODUCT_ID" }}-charts/web
+  # snip
+```
+
+And reusing it from the two product helmfiles:
+
+
+`product1/helmfile.yaml`:
+
+```yaml
+helmfiles:
+- ../observability/helmfile.yaml
+- ../product/helmfile.yaml
+```
+
+`product2/helmfile.yaml`:
+
+```yaml
+helmfiles:
+- ../observability/helmfile.yaml
+- ../product/helmfile.yaml
+```
+
+Now that we use the environment variable `PRODUCT_ID` to as the parameters of release names, you need to set it before running `helmfile`, so that it produces the differently named releases per product:
+
+```console
+$ PRODUCT_ID=1 helmfile -f product1/helmfile.yaml apply
+$ PRODUCT_ID=2 helmfile -f product2/helmfile.yaml apply
+```