feat(promtail): add promtail job and configuration

Signed-off-by: Bruce Becker <[email protected]>

promtail.nomad

@@ -0,0 +1,97 @@
+# There can only be a single job definition per file. This job is named
+# "example" so it will create a job with the ID and Name "example".
+
+# The "job" stanza is the top-most configuration option in the job
+# specification. A job is a declarative specification of tasks that Nomad
+# should run. Jobs have a globally unique name, one or many task groups, which
+# are themselves collections of one or many tasks.
+#
+# For more information and examples on the "job" stanza, please see
+# the online documentation at:
+#
+#     https://www.nomadproject.io/docs/job-specification/job
+#
+job "promtail" {
+  datacenters = ["dc1"]
+  type = "system"
+  // constraint {
+  //   attribute = "${node.class}"
+  //   operator = "regexp"
+  //   value = "32|64"
+  // }
+
+  group "promtail" {
+    count = 1
+
+    network {
+      port "http" {
+        static = 9080
+      }
+    }
+
+    service {
+      name = "promtail"
+      tags = ["logs", "promtail", "observability"]
+      port = "http"
+
+      check {
+        name     = "promtail-alive"
+        type     = "tcp"
+        interval = "10s"
+        timeout  = "2s"
+      }
+
+    }
+
+    restart {
+      # The number of attempts to run the job within the specified interval.
+      attempts = 2
+      interval = "30m"
+
+      # The "delay" parameter specifies the duration to wait before restarting
+      # a task after it has failed.
+      delay = "15s"
+
+      # The "mode" parameter controls what happens when a task has restarted
+      # "attempts" times within the interval. "delay" mode delays the next
+      # restart until the next interval. "fail" mode does not restart the task
+      # if "attempts" has been hit within the interval.
+      mode = "fail"
+    }
+
+    ephemeral_disk {
+      size = 300
+    }
+
+    task "promtail" {
+      # The "driver" parameter specifies the task driver that should be used to
+      # run the task.
+      driver = "raw_exec"
+
+      config {
+        command = "promtail"
+        args = ["-config.file=local/promtail.yml"]
+      }
+
+      artifact {
+         source = "http://minio-deploy-run.service.consul:9000/loki-bin/promtail-linux-${attr.cpu.arch}.zip"
+         destination = "local/promtail"
+         mode = "file"
+      }
+
+
+      resources {
+        cpu    = 500 # 500 MHz
+        memory = 256 # 256MB
+      }
+
+
+      template {
+         data          = file("promtail.yml.tpl")
+         destination   = "local/promtail.yml"
+         change_mode   = "signal"
+         change_signal = "SIGHUP"
+      }
+    }
+  }
+}

promtail.yml.tpl

@@ -0,0 +1,18 @@
+server:
+  http_listen_port: 9080
+  grpc_listen_port: 0
+
+positions:
+  filename: /tmp/positions.yaml
+
+clients:
+  - url: http://loki-http-server.service.consul:3100/loki/api/v1/push
+
+scrape_configs:
+- job_name: system
+  static_configs:
+  - targets:
+      - localhost
+    labels:
+      job: consul
+      __path__: /var/log/consul*.log