How to enable Consul maintenance mode

Enable HashiCorp Consul maintenance mode.

List Consul nodes.

$ consul members

Node      Address             Status  Type    Build   Protocol  DC        Partition  Segment
consul-1  172.16.148.11:8301  alive   server  1.12.2  2         dc-lab-1  default    <all>
consul-2  172.16.148.12:8301  alive   server  1.12.2  2         dc-lab-1  default    <all>
consul-3  172.16.148.13:8301  alive   server  1.12.2  2         dc-lab-1  default    <all>

Place a current node into maintenance mode.

consul-2$ consul maint -enable -reason "security update"

Node maintenance is now enabled

Inspect maintenance status on the current node.

consul-2$ consul maint

Node:
  Name:   consul-2
  Reason: security update

Inspect maintenance for specific node.

$ curl --silent http://127.0.0.1:8500/v1/health/node/consul-2 | jq .

[
  {
    "Node": "consul-2",
    "CheckID": "_node_maintenance",
    "Name": "Node Maintenance Mode",
    "Status": "critical",
    "Notes": "security update",
    "Output": "",
    "ServiceID": "",
    "ServiceName": "",
    "ServiceTags": [],
    "Type": "maintenance",
    "Interval": "",
    "Timeout": "",
    "ExposedPort": 0,
    "Definition": {},
    "CreateIndex": 228618,
    "ModifyIndex": 228618
  },
  {
    "Node": "consul-2",
    "CheckID": "serfHealth",
    "Name": "Serf Health Status",
    "Status": "passing",
    "Notes": "",
    "Output": "Agent alive and reachable",
    "ServiceID": "",
    "ServiceName": "",
    "ServiceTags": [],
    "Type": "",
    "Interval": "",
    "Timeout": "",
    "ExposedPort": 0,
    "Definition": {},
    "CreateIndex": 9,
    "ModifyIndex": 2015
  }
]

Disable maintenance mode on a current node.

consul-2$ consul maint -disable

Node maintenance is now disabled

Inspect maintenance for specific node.

$ curl --silent http://127.0.0.1:8500/v1/health/node/consul-2 | jq .

[
  {
    "Node": "consul-2",
    "CheckID": "serfHealth",
    "Name": "Serf Health Status",
    "Status": "passing",
    "Notes": "",
    "Output": "Agent alive and reachable",
    "ServiceID": "",
    "ServiceName": "",
    "ServiceTags": [],
    "Type": "",
    "Interval": "",
    "Timeout": "",
    "ExposedPort": 0,
    "Definition": {},
    "CreateIndex": 9,
    "ModifyIndex": 2015
  }
]