Passing a sidecar_task stanza to one task modifies every other connect sidecar task

[jorgemarey]

Nomad version

Nomad v0.11.3

Issue

When providing a sidecar_task stanza to a group service to modify sidecar configuration, if the
config is modified this will be used in every other connect sidecar (over other groups of the same job, or even
in different jobs deployed later.)

Reproduction steps

1. start nomad with connect (nomad agent -dev-connect)
2. run job
3. all envoy tasks will have the same config (even if no sidecar_task stanza is specified)
4. deploying a new different job will have the same sidecar configuration as the one specified in the previous jobs

Job file (if appropriate)

job "countdash" {
   datacenters = ["dc1"]
   group "api" {
     network {
       mode = "bridge"
     }

     service {
       name = "count-api"
       port = "9001"

       connect {
         sidecar_service {}
       }
     }

     task "web" {
       driver = "docker"
       config {
         image = "hashicorpnomad/counter-api:v1"
       }
     }
   }

   group "dashboard" {
     network {
       mode ="bridge"
       port "http" {
         static = 9002
         to     = 9002
       }
     }

     service {
       name = "count-dashboard"
       port = "9002"

       connect {
         sidecar_service {
           proxy {
             upstreams {
               destination_name = "count-api"
               local_bind_port = 8080
             }
           }
         }
         sidecar_task {
           config {
             args = [ "-l", "debug"]
           }
         }
       }
     }

     task "dashboard" {
       driver = "docker"
       env {
         COUNTING_SERVICE_URL = "http://${NOMAD_UPSTREAM_ADDR_count_api}"
       }
       config {
         image = "hashicorpnomad/counter-dashboard:v1"
       }
     }
   }
 }

[dpn]

So we've bumped into this into a test cluster-- is there a way to revert this change back to the default config? I'm guessing this is a wipe the cluster and start over kind of situation but, happy to try other things if anyone has any ideas.

Edit: Looks like a rolling restart of the servers was enough in case anyone runs across this 👍

[github-actions]

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