Update deployment workflows

blog.nomad.hcl

@@ -16,6 +16,10 @@ job "blog" {
   group "blog" {
     count = 1
 
+    # let Consul/Traefik deregister the old allocation before it exits,
+    # so no requests are routed to it during a rolling switchover
+    shutdown_delay = "10s"
+
     network {
       port "http" {
         to = 3000
@@ -52,6 +56,18 @@ job "blog" {
         "traefik.http.services.blog-svc.loadbalancer.healthcheck.timeout=2s",
         "traefik.http.services.blog-svc.loadbalancer.healthcheck.hostname=${local.HOST}",
       ]
+
+      # canary allocations register with these tags instead, so Traefik
+      # does not route production traffic to them before promotion
+      canary_tags = ["canary"]
+
+      check {
+        name     = "blog-health"
+        type     = "http"
+        path     = "/healthz"
+        interval = "10s"
+        timeout  = "2s"
+      }
     }
 
     task "blog" {
@@ -65,8 +81,11 @@ job "blog" {
 
     update {
       max_parallel     = 1
+      health_check     = "checks"
       min_healthy_time = "10s"
       healthy_deadline = "3m"
+      canary           = 1
+      auto_promote     = true
       auto_revert      = true
     }
   }