feat(nginx): nginx job (#71)

feat(nginx): initial commit of nginx job
fix(nginx): add migrate and update stanzas

---------

Signed-off-by: Bruce Becker <brucellino@protonmail.com>

nginx.nomad

@@ -0,0 +1,95 @@
+job "nginx" {
+  datacenters = ["dc1"]
+  update {
+    max_parallel      = 2
+    health_check      = "checks"
+    min_healthy_time  = "10s"
+    healthy_deadline  = "5m"
+    progress_deadline = "10m"
+    auto_revert       = true
+    auto_promote      = true
+    canary            = 1
+    stagger           = "30s"
+  }
+  migrate {
+    max_parallel     = 1
+    health_check     = "checks"
+    min_healthy_time = "10s"
+    healthy_deadline = "5m"
+  }
+  group "nginx" {
+    count = 1
+
+    network {
+      mode = "bridge"
+      port "http" { static = 80 }
+    }
+
+    service {
+      name = "nginx"
+      port = "http"
+      // connect {
+      //   sidecar_service {
+      //     disable_default_tcp_check = true
+      //   }
+      // }
+      check {
+        name     = "nginx_alive"
+        type     = "tcp"
+        interval = "10s"
+        timeout  = "1s"
+      }
+
+      check {
+        name     = "nginx_http_alive"
+        type     = "http"
+        port     = "http"
+        path     = "/nginx_status"
+        interval = "5s"
+        timeout  = "2s"
+      }
+    }
+
+    task "nginx" {
+      driver = "docker"
+      resources {
+        cpu    = 1000
+        memory = 512
+      }
+      config {
+        image = "nginx:stable-alpine-slim"
+        // privileged = true
+        ports        = ["http"]
+        network_mode = "bridge"
+        volumes = [
+          "local:/etc/nginx/conf.d",
+        ]
+      }
+
+      template {
+        data          = <<EOF
+upstream backend {
+{{ range service "promtail" }}
+  server {{ .Address }}:{{ .Port }};
+{{ else }}server 127.0.0.1:65535; # force a 502
+{{ end }}
+}
+
+server {
+  listen 80;
+  location /nginx_status {
+    stub_status on;
+    allow 127.0.0.1;
+  }
+  location /promtail {
+    proxy_pass http://backend;
+  }
+}
+EOF
+        destination   = "local/load-balancer.conf"
+        change_mode   = "signal"
+        change_signal = "SIGHUP"
+      }
+    }
+  }
+}