Merge pull request 'loki-monitoring02' (#41) from loki-monitoring02 into master

Reviewed-on: #41

.gitignore

@@ -2,6 +2,9 @@
 result
 result-*
 
+# MCP config (contains secrets)
+.mcp.json
+
 # Terraform/OpenTofu
 terraform/.terraform/
 terraform/.terraform.lock.hcl

.mcp.json.example

@@ -20,7 +20,9 @@
       "env": {
         "PROMETHEUS_URL": "https://prometheus.home.2rjus.net",
         "ALERTMANAGER_URL": "https://alertmanager.home.2rjus.net",
-        "LOKI_URL": "http://monitoring01.home.2rjus.net:3100"
+        "LOKI_URL": "https://loki.home.2rjus.net",
+        "LOKI_USERNAME": "promtail",
+        "LOKI_PASSWORD": "<password from: bao kv get -field=password secret/shared/loki/push-auth>"
       }
     },
     "homelab-deploy": {
@@ -44,4 +46,3 @@
     }
   }
 }
-

docs/plans/monitoring-migration-victoriametrics.md

@@ -14,8 +14,8 @@ a `monitoring` CNAME for seamless transition.
 - Alertmanager (routes to alerttonotify webhook)
 - Grafana (dashboards, datasources)
 - Loki (log aggregation from all hosts via Promtail)
-- Tempo (distributed tracing)
-- Pyroscope (continuous profiling)
+- Tempo (distributed tracing) - not actively used
+- Pyroscope (continuous profiling) - not actively used
 
 **Hardcoded References to monitoring01:**
 - `system/monitoring/logs.nix` - Promtail sends logs to `http://monitoring01.home.2rjus.net:3100`
@@ -44,9 +44,7 @@ If multi-year retention with downsampling becomes necessary later, Thanos can be
                      │  VictoriaMetrics│
                      │  + Grafana      │
      monitoring      │  + Loki         │
-     CNAME ──────────│  + Tempo        │
-                     │  + Pyroscope    │
-                     │  + Alertmanager │
+     CNAME ──────────│  + Alertmanager │
                      │  (vmalert)      │
                      └─────────────────┘
                             ▲
@@ -94,16 +92,11 @@ Imported by monitoring02 alongside the existing Grafana service.
 4. **Grafana** (port 3000): [DONE]
    - VictoriaMetrics datasource (localhost:8428) as default
    - monitoring01 Prometheus datasource kept for comparison during parallel operation
-   - Loki datasource pointing to monitoring01 (until Loki migrated)
+   - Loki datasource pointing to localhost (after Loki migrated to monitoring02)
 
-5. **Loki** (port 3100):
-   - TODO: Same configuration as current
-
-6. **Tempo** (ports 3200, 3201):
-   - TODO: Same configuration
-
-7. **Pyroscope** (port 4040):
-   - TODO: Same Docker-based deployment
+5. **Loki** (port 3100): [DONE]
+   - Same configuration as monitoring01 in standalone `services/loki/` module
+   - Grafana datasource updated to localhost:3100
 
 **Note:** pve-exporter and pushgateway scrape targets are not included on monitoring02.
 pve-exporter requires a local exporter instance; pushgateway is replaced by VictoriaMetrics
@@ -147,7 +140,6 @@ Update hardcoded references to use the CNAME:
    - prometheus.home.2rjus.net -> monitoring.home.2rjus.net:8428
    - alertmanager.home.2rjus.net -> monitoring.home.2rjus.net:9093
    - grafana.home.2rjus.net -> monitoring.home.2rjus.net:3000
-   - pyroscope.home.2rjus.net -> monitoring.home.2rjus.net:4040
 
 Note: `hosts/template2/bootstrap.nix` stays pointed at monitoring01 until decommission.
 
@@ -172,8 +164,8 @@ Once ready to cut over:
 ## Current Progress
 
 - **Phase 1** complete (2026-02-08): monitoring02 host created, Grafana with Kanidm OIDC validated
-- **Phase 2** in progress (2026-02-17): VictoriaMetrics, vmalert, Alertmanager, Grafana datasources configured
-  - Remaining: Loki, Tempo, Pyroscope migration
+- **Phase 2** complete (2026-02-17): VictoriaMetrics, vmalert, Alertmanager, Loki, Grafana datasources configured
+  - Tempo and Pyroscope deferred (not actively used; can be added later if needed)
 
 ## Open Questions
 

hosts/monitoring02/configuration.nix

@@ -18,7 +18,7 @@
     role = "monitoring";
   };
 
-  homelab.dns.cnames = [ "grafana-test" "metrics" "vmalert" ];
+  homelab.dns.cnames = [ "grafana-test" "metrics" "vmalert" "loki" ];
 
   # Enable Vault integration
   vault.enable = true;

hosts/monitoring02/default.nix

@@ -3,5 +3,6 @@
     ./configuration.nix
     ../../services/grafana
     ../../services/victoriametrics
+    ../../services/loki
   ];
 }

services/grafana/default.nix

@@ -54,7 +54,7 @@
         {
           name = "Loki";
           type = "loki";
-          url = "http://monitoring01.home.2rjus.net:3100";
+          url = "http://localhost:3100";
           uid = "loki";
         }
       ];

services/loki/default.nix

@@ -0,0 +1,104 @@
+{ config, lib, pkgs, ... }:
+let
+  # Script to generate bcrypt hash from Vault password for Caddy basic_auth
+  generateCaddyAuth = pkgs.writeShellApplication {
+    name = "generate-caddy-loki-auth";
+    runtimeInputs = [ config.services.caddy.package ];
+    text = ''
+      PASSWORD=$(cat /run/secrets/loki-push-auth)
+      HASH=$(caddy hash-password --plaintext "$PASSWORD")
+      echo "LOKI_PUSH_HASH=$HASH" > /run/secrets/caddy-loki-auth.env
+      chmod 0400 /run/secrets/caddy-loki-auth.env
+    '';
+  };
+in
+{
+  # Fetch Loki push password from Vault
+  vault.secrets.loki-push-auth = {
+    secretPath = "shared/loki/push-auth";
+    extractKey = "password";
+    services = [ "caddy" ];
+  };
+
+  # Generate bcrypt hash for Caddy before it starts
+  systemd.services.caddy-loki-auth = {
+    description = "Generate Caddy basic auth hash for Loki";
+    after = [ "vault-secret-loki-push-auth.service" ];
+    requires = [ "vault-secret-loki-push-auth.service" ];
+    before = [ "caddy.service" ];
+    requiredBy = [ "caddy.service" ];
+    serviceConfig = {
+      Type = "oneshot";
+      RemainAfterExit = true;
+      ExecStart = lib.getExe generateCaddyAuth;
+    };
+  };
+
+  # Load the bcrypt hash as environment variable for Caddy
+  services.caddy.environmentFile = "/run/secrets/caddy-loki-auth.env";
+
+  # Caddy reverse proxy for Loki with basic auth
+  services.caddy.virtualHosts."loki.home.2rjus.net".extraConfig = ''
+    basic_auth {
+      promtail {env.LOKI_PUSH_HASH}
+    }
+    reverse_proxy http://127.0.0.1:3100
+  '';
+
+  services.loki = {
+    enable = true;
+    configuration = {
+      auth_enabled = false;
+
+      server = {
+        http_listen_address = "127.0.0.1";
+        http_listen_port = 3100;
+      };
+      common = {
+        ring = {
+          instance_addr = "127.0.0.1";
+          kvstore = {
+            store = "inmemory";
+          };
+        };
+        replication_factor = 1;
+        path_prefix = "/var/lib/loki";
+      };
+      schema_config = {
+        configs = [
+          {
+            from = "2024-01-01";
+            store = "tsdb";
+            object_store = "filesystem";
+            schema = "v13";
+            index = {
+              prefix = "loki_index_";
+              period = "24h";
+            };
+          }
+        ];
+      };
+      storage_config = {
+        filesystem = {
+          directory = "/var/lib/loki/chunks";
+        };
+      };
+      compactor = {
+        working_directory = "/var/lib/loki/compactor";
+        compaction_interval = "10m";
+        retention_enabled = true;
+        retention_delete_delay = "2h";
+        retention_delete_worker_count = 150;
+        delete_request_store = "filesystem";
+      };
+      limits_config = {
+        retention_period = "30d";
+        ingestion_rate_mb = 10;
+        ingestion_burst_size_mb = 20;
+        max_streams_per_user = 10000;
+        max_query_series = 500;
+        max_query_parallelism = 8;
+      };
+    };
+  };
+}

system/monitoring/logs.nix

@@ -16,6 +16,16 @@ in
       SystemKeepFree=1G
     '';
   };
+
+  # Fetch Loki push password from Vault (only on hosts with Vault enabled)
+  vault.secrets.promtail-loki-auth = lib.mkIf config.vault.enable {
+    secretPath = "shared/loki/push-auth";
+    extractKey = "password";
+    owner = "promtail";
+    group = "promtail";
+    services = [ "promtail" ];
+  };
+
   # Configure promtail
   services.promtail = {
     enable = true;
@@ -31,6 +41,14 @@ in
         {
           url = "http://monitoring01.home.2rjus.net:3100/loki/api/v1/push";
         }
+      ] ++ lib.optionals config.vault.enable [
+        {
+          url = "https://loki.home.2rjus.net/loki/api/v1/push";
+          basic_auth = {
+            username = "promtail";
+            password_file = "/run/secrets/promtail-loki-auth";
+          };
+        }
       ];
 
       scrape_configs = [

terraform/vault/approle.tf

@@ -26,6 +26,17 @@ path "secret/data/shared/nixos-exporter/*" {
 EOT
 }
 
+# Shared policy for Loki push authentication (all hosts push logs)
+resource "vault_policy" "loki_push" {
+  name = "loki-push"
+
+  policy = <<EOT
+path "secret/data/shared/loki/*" {
+  capabilities = ["read", "list"]
+}
+EOT
+}
+
 # Define host access policies
 locals {
   host_policies = {
@@ -78,7 +89,7 @@ locals {
       ]
     }
 
-    # Wave 3: DNS servers
+    # Wave 3: DNS servers (managed in hosts-generated.tf)
 
     # Wave 4: http-proxy
     "http-proxy" = {
@@ -138,7 +149,7 @@ resource "vault_approle_auth_backend_role" "hosts" {
   backend   = vault_auth_backend.approle.path
   role_name = each.key
   token_policies = concat(
-    ["${each.key}-policy", "homelab-deploy", "nixos-exporter"],
+    ["${each.key}-policy", "homelab-deploy", "nixos-exporter", "loki-push"],
     lookup(each.value, "extra_policies", [])
   )
 

terraform/vault/hosts-generated.tf

@@ -74,7 +74,7 @@ resource "vault_approle_auth_backend_role" "generated_hosts" {
 
   backend            = vault_auth_backend.approle.path
   role_name          = each.key
-  token_policies     = ["host-${each.key}", "homelab-deploy", "nixos-exporter"]
+  token_policies     = ["host-${each.key}", "homelab-deploy", "nixos-exporter", "loki-push"]
   secret_id_ttl      = 0 # Never expire (wrapped tokens provide time limit)
   token_ttl          = 3600
   token_max_ttl      = 3600

terraform/vault/secrets.tf

@@ -153,6 +153,12 @@ locals {
       auto_generate   = true
       password_length = 64
     }
+
+    # Loki push authentication (used by Promtail on all hosts)
+    "shared/loki/push-auth" = {
+      auto_generate   = true
+      password_length = 32
+    }
   }
 }