Add Loki documentation

gitops/components/loki/README.md

@@ -0,0 +1,51 @@
+# Loki
+Loki is a logging aggregator from Grafana labs. It has native support in Grafana as a data source.
+
+This configuration deploys Loki in `singleBinary` mode (monolithic style), using S3 for log storage.
+
+## Required Variables
+* `LOKI_GATEWAY_HOST`: The hostname of the loki gateway ingress
+* `LOKI_ROLE_ARN`: The role ARN to attach to the loki service account
+* `LOKI_S3_BUCKET`: The name of the loki log storage bucket
+
+## Required Secrets
+A secret named `loki-basic-auth` in the `loki` namespace, which contains the basic auth credentials for the Loki gateway. See [this tutorial](https://kubernetes.github.io/ingress-nginx/examples/auth/basic/) for an example on how to generate such a secret.
+
+## Required AWS Resources
+* An S3 bucket for log storage
+* IAM policy for the `loki` service account:
+```json
+{
+    "Version": "2012-10-17",
+    "Statement": [
+        {
+            "Effect": "Allow",
+            "Action": [
+                "s3:ListBucket",
+                "s3:PutObject",
+                "s3:GetObject",
+                "s3:DeleteObject"
+            ],
+            "Resource": [
+                "arn:aws:s3:::{LOKI_S3_BUCKET}",
+                "arn:aws:s3:::{LOKI_S3_BUCKET}/*"
+            ]
+        }
+    ]
+}
+```
+* If using grafana, a data source for Loki:
+```hcl
+resource "grafana_data_source" "loki" {
+  provider            = grafana.amg
+  type                = "loki"
+  name                = "loki"
+  url                 = "{LOKI_GATEWAY_HOST}"
+  basic_auth_enabled  = true
+  basic_auth_username = "admin"
+
+  secure_json_data_encoded = jsonencode({
+    basicAuthPassword = var.LOKI_BASIC_AUTH_PASSWD
+  })
+}
+```

gitops/components/loki/resources.yaml

@@ -92,9 +92,8 @@ spec:
             ingressClassName: "nginx"
             annotations:
               cert-manager.io/cluster-issuer: letsencrypt
-              # TODO setup auth
-              # nginx.ingress.kubernetes.io/auth-type: basic
-              # nginx.ingress.kubernetes.io/auth-secret: loki-basic-auth
+              nginx.ingress.kubernetes.io/auth-type: basic
+              nginx.ingress.kubernetes.io/auth-secret: loki-basic-auth
             hosts:
               - host: loki.example.com
                 paths: