If the local Consul agent is not available while attempting to step down from active or up to active, retry once a second. Allow for concurrent changes to the state with a single registration updater. Fix standby initialization.
Vault will now register itself with Consul. The active node can be found using `active.vault.service.consul`. All standby vaults are available via `standby.vault.service.consul`. All unsealed vaults are considered healthy and available via `vault.service.consul`. Change in status and registration is event driven and should happen at the speed of a write to Consul (~network RTT + ~1x fsync(2)).
Healthy/active:
```
curl -X GET 'http://127.0.0.1:8500/v1/health/service/vault?pretty' && echo;
[
{
"Node": {
"Node": "vm1",
"Address": "127.0.0.1",
"TaggedAddresses": {
"wan": "127.0.0.1"
},
"CreateIndex": 3,
"ModifyIndex": 20
},
"Service": {
"ID": "vault:127.0.0.1:8200",
"Service": "vault",
"Tags": [
"active"
],
"Address": "127.0.0.1",
"Port": 8200,
"EnableTagOverride": false,
"CreateIndex": 17,
"ModifyIndex": 20
},
"Checks": [
{
"Node": "vm1",
"CheckID": "serfHealth",
"Name": "Serf Health Status",
"Status": "passing",
"Notes": "",
"Output": "Agent alive and reachable",
"ServiceID": "",
"ServiceName": "",
"CreateIndex": 3,
"ModifyIndex": 3
},
{
"Node": "vm1",
"CheckID": "vault-sealed-check",
"Name": "Vault Sealed Status",
"Status": "passing",
"Notes": "Vault service is healthy when Vault is in an unsealed status and can become an active Vault server",
"Output": "",
"ServiceID": "vault:127.0.0.1:8200",
"ServiceName": "vault",
"CreateIndex": 19,
"ModifyIndex": 19
}
]
}
]
```
Healthy/standby:
```
[snip]
"Service": {
"ID": "vault:127.0.0.2:8200",
"Service": "vault",
"Tags": [
"standby"
],
"Address": "127.0.0.2",
"Port": 8200,
"EnableTagOverride": false,
"CreateIndex": 17,
"ModifyIndex": 20
},
"Checks": [
{
"Node": "vm2",
"CheckID": "serfHealth",
"Name": "Serf Health Status",
"Status": "passing",
"Notes": "",
"Output": "Agent alive and reachable",
"ServiceID": "",
"ServiceName": "",
"CreateIndex": 3,
"ModifyIndex": 3
},
{
"Node": "vm2",
"CheckID": "vault-sealed-check",
"Name": "Vault Sealed Status",
"Status": "passing",
"Notes": "Vault service is healthy when Vault is in an unsealed status and can become an active Vault server",
"Output": "",
"ServiceID": "vault:127.0.0.2:8200",
"ServiceName": "vault",
"CreateIndex": 19,
"ModifyIndex": 19
}
]
}
]
```
Sealed:
```
"Checks": [
{
"Node": "vm2",
"CheckID": "serfHealth",
"Name": "Serf Health Status",
"Status": "passing",
"Notes": "",
"Output": "Agent alive and reachable",
"ServiceID": "",
"ServiceName": "",
"CreateIndex": 3,
"ModifyIndex": 3
},
{
"Node": "vm2",
"CheckID": "vault-sealed-check",
"Name": "Vault Sealed Status",
"Status": "critical",
"Notes": "Vault service is healthy when Vault is in an unsealed status and can become an active Vault server",
"Output": "Vault Sealed",
"ServiceID": "vault:127.0.0.2:8200",
"ServiceName": "vault",
"CreateIndex": 19,
"ModifyIndex": 38
}
]
```
No signal handler was setup to receive SIGINT. I didn't investigate to
see if signal(2) mask was setup (ala `SIG_IGN`) or if sigprocmask(2) is
being used, but in either case, the correct behavior is to capture and
treat SIGINT the same as SIGTERM. At some point in the future these two
signals may affect the running process differently, but we will clarify
that difference in the future.
