Add section on advanced autopilot features to the guide

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Kyle Havlovitz 2017-03-28 11:56:21 -07:00
parent b7207b1733
commit 4f9a57cda3
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2 changed files with 77 additions and 8 deletions

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@ -885,6 +885,9 @@ Consul will not enable TLS for the HTTP API unless the `https` port has been ass
* <a name="server"></a><a href="#server">`server`</a> Equivalent to the
[`-server` command-line flag](#_server).
* <a name="non_voting_server"></a><a href="#non_voting_server">`non_voting_server`</a> - Equivalent to the
[`-non-voting-server` command-line flag](#_non_voting_server).
* <a name="server_name"></a><a href="#server_name">`server_name`</a> When provided, this overrides
the [`node_name`](#_node) for the TLS certificate. It can be used to ensure that the certificate
name matches the hostname we declare.

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@ -35,6 +35,8 @@ CleanupDeadServers = true
LastContactThreshold = 200ms
MaxTrailingLogs = 250
ServerStabilizationTime = 10s
RedundancyZoneTag = ""
DisableUpgradeMigration = false
$ consul operator autopilot set-config -cleanup-dead-servers=false
Configuration updated!
@ -44,6 +46,8 @@ CleanupDeadServers = false
LastContactThreshold = 200ms
MaxTrailingLogs = 250
ServerStabilizationTime = 10s
RedundancyZoneTag = ""
DisableUpgradeMigration = false
```
## Dead Server Cleanup
@ -87,22 +91,30 @@ $ curl localhost:8500/v1/operator/autopilot/health
{
"ID": "e349749b-3303-3ddf-959c-b5885a0e1f6e",
"Name": "node1",
"Address": "127.0.0.1:8300",
"SerfStatus": "alive",
"Version": "0.8.0",
"Leader": true,
"LastContact": "0s",
"LastTerm": 3,
"LastIndex": 23,
"LastTerm": 2,
"LastIndex": 10,
"Healthy": true,
"StableSince": "2017-03-10T22:01:14Z"
"Voter": true,
"StableSince": "2017-03-28T18:28:52Z"
},
{
"ID": "099061c7-ea74-42d5-be04-a0ad74caaaf5",
"ID": "e35bde83-4e9c-434f-a6ef-453f44ee21ea",
"Name": "node2",
"Address": "127.0.0.1:8705",
"SerfStatus": "alive",
"LastContact": "53.279635ms",
"LastTerm": 3,
"LastIndex": 23,
"Version": "0.8.0",
"Leader": false,
"LastContact": "35.371007ms",
"LastTerm": 2,
"LastIndex": 10,
"Healthy": true,
"StableSince": "2017-03-10T22:03:26Z"
"Voter": false,
"StableSince": "2017-03-28T18:29:10Z"
}
]
}
@ -114,3 +126,57 @@ When a new server is added to the cluster, there is a waiting period where it
must be healthy and stable for a certain amount of time before being promoted
to a full, voting member. This can be configured via the `ServerStabilizationTime`
setting.
---
~> The following Autopilot features are available only in
[Consul Enterprise](https://www.hashicorp.com/consul.html) version 0.8.0 and later.
## Designated Non-voting Servers
With the [`-non-voting-server`](/docs/agent/options.html#_non_voting_server) option, a
server can be explicitly marked as a non-voter and will never be promoted to a voting
member. This can be useful when more read scaling is needed; being a non-voter means
that the server will still have data replicated to it, but it will not be part of the
quorum that the leader must wait for before committing log entries.
## Redundancy Zones
Prior to Autopilot, it was difficult to deploy servers in a way that took advantage of
isolated failure domains such as AWS Availability Zones; users would be forced to either
have an overly-large quorum (2-3 nodes per AZ) or give up redundancy within an AZ by
deploying just one server in each.
If the `RedundancyZoneTag` setting is set, Consul will use its value to look for a
zone in each server's specified [`-node-meta`](/docs/agent/options.html#_node_meta)
tag. For example, if `RedundancyZoneTag` is set to `zone`, and `-node-meta zone:east1a`
is used when starting a server, that server's redundancy zone will be `east1a`.
Consul will then use these values to partition the servers by redundancy zone, and will
aim to keep one voting server per zone. Extra servers in each zone will stay as non-voters
on standby to be promoted if the active voter leaves or dies.
## Upgrade Migrations
Autopilot in Consul Enterprise supports upgrade migrations by default. To disable this
functionality, set `DisableUpgradeMigration` to true.
When a new server is added and Autopilot detects that its Consul version is newer than
that of the existing servers, Autopilot will avoid promoting the new server until enough
newer-versioned servers have been added to the cluster. When the count of new servers
equals or exceeds that of the old servers, Autopilot will begin promoting the new servers
to voters and demoting the old servers. After this is finished, the old servers can be
safely removed from the cluster.
To check the consul version of the servers, either the [autopilot health]
(/docs/agent/http/operator.html#autopilot-health) endpoint or the `consul members`
command can be used:
```
$ consul members
Node Address Status Type Build Protocol DC
node1 127.0.0.1:8301 alive server 0.7.5 2 dc1
node2 127.0.0.1:8703 alive server 0.7.5 2 dc1
node3 127.0.0.1:8803 alive server 0.7.5 2 dc1
node4 127.0.0.1:8203 alive server 0.8.0 2 dc1
```