How to configure granular ingress in COS¶

Both COS and COS Lite allow you to configure Traefik ingress for certain internal components. This configuration determines which applications are integrated with Traefik via an ingress interface; routing their traffic through Traefik.

        %%{init: { "theme": "dark" } }%%
flowchart LR
  user([External traffic])

  subgraph COS [cos-model]
    traefik[traefik]
    grafana[grafana]
    alertmanager[alertmanager]
    catalogue[catalogue]
    loki[loki]
    prometheus[prometheus]
  end

  user --> traefik
  traefik -->|"ingress = true"| grafana
  traefik -. "ingress = false" .-> alertmanager
  traefik -. "ingress = false" .-> catalogue
  traefik -. "ingress = false" .-> loki
  traefik -. "ingress = false" .-> prometheus

  classDef Charm stroke:white,stroke-width:1px,color:white,rx:8px,ry:8px
  classDef Disabled stroke:#666,stroke-width:1px,color:#aaa,rx:8px,ry:8px
  class traefik,grafana,user Charm
  class alertmanager,catalogue,loki,prometheus Disabled

Configure the Terraform module¶

Note

If you are using COS Lite, create a cos-lite module with the cos-lite source: git::https://github.com/canonical/observability-stack//terraform/cos-lite.

The COS Lite bundle is now deprecated in favor of Terraform modules.

Using the following Terraform module, set your ingress options to enable or disable routing traffic through Traefik.

module "cos" {
  # Use the right source value depending on whether you are using cos or cos-lite
  source = "git::https://github.com/canonical/observability-stack//terraform/cos?ref=main"

  # ... other inputs ...

  # Toggle a component's ingress integration to Traefik.
  ingress = {
    alertmanager = false
    catalogue    = false
    grafana      = true # only enable ingress for Grafana
    loki         = false
    prometheus   = false
  }
}

The ingress variable determines if a COS-internal traefik application is deployed and integrated with COS components for ingress. If at least one application is configured for ingress, then traefik will exist internally, otherwise not.

Ensure that you have provided any required variables (update the ... other inputs ... placeholder) for the respective COS module before applying the configuration, by running terraform apply.