mirror of https://github.com/status-im/consul.git
59 lines
2.8 KiB
Markdown
59 lines
2.8 KiB
Markdown
# Agent Configuration
|
|
|
|
The [Agent Configuration] is the primary mechanism for configuring Consul. Agent
|
|
Configuration also allows for specifying [Config Entries], [Services], and [Checks] that
|
|
will be loaded when the agent starts.
|
|
|
|
Most configuration comes from [hcl] or `json` files, but some configuration can also be
|
|
specified using command line flags, and some can be loaded with [Auto-Config].
|
|
|
|
See also the [checklist for adding a new field] to the configuration.
|
|
|
|
[hcl]: https://github.com/hashicorp/hcl/tree/hcl1
|
|
[Agent Configuration]: https://www.consul.io/docs/agent/config
|
|
[checklist for adding a new field]: ./checklist-adding-config-fields.md
|
|
[Auto-Config]: #auto-config
|
|
[Config Entries]: https://www.consul.io/docs/agent/config/config-files#config_entries
|
|
[Services]: https://www.consul.io/docs/discovery/services
|
|
[Checks]: https://www.consul.io/docs/discovery/checks
|
|
|
|
|
|
## Code
|
|
|
|
The Agent Configuration is implemented in [agent/config], and the primary entrypoint is
|
|
[Load]. Config loading is performed in phases:
|
|
|
|
1. Command line flags are used to create a `config.LoadOpts` and passed to `Load`.
|
|
2. `Load` reads all the config files and builds an ordered list of `config.Source`.
|
|
3. Each `config.Source` is read to produce a `config.Config`.
|
|
4. Each `config.Config` is merged ontop the previous.
|
|
5. A `config.RuntimeConfig` is produced from the merged `config.Config`
|
|
6. The `config.RuntimeConfig` is validated.
|
|
7. Finally a result is returned with the `RuntimeConfig` and any warnings, or an error.
|
|
|
|
[agent/config]: https://github.com/hashicorp/consul/tree/main/agent/config
|
|
[Load]: https://pkg.go.dev/github.com/hashicorp/consul/agent/config#Load
|
|
|
|
If [Auto-Config] is enabled, when it receives the config from the server, the
|
|
entire process is repeated a second time with the addition config provided as another
|
|
`config.Source`.
|
|
|
|
Default values can be specified in one of the [default sources] or set when
|
|
converting from `Config` to `RuntimeConfig` in [builder.build]. Hopefully in the future we
|
|
should remove one of those ways of setting default values.
|
|
|
|
[default sources]: https://github.com/hashicorp/consul/blob/main/agent/config/default.go
|
|
[builder.build]: https://github.com/hashicorp/consul/blob/main/agent/config/builder.go
|
|
|
|
## Auto-Config
|
|
|
|
Auto-Config is enabled by the [auto_config] field in an Agent Configuration file. It is
|
|
implemented in a couple packages.
|
|
|
|
* the server RPC endpoint is in [agent/consul/auto_config_endpoint.go]
|
|
* the client that receives and applies the config is implemented in [agent/auto-config]
|
|
|
|
[auto_config]: https://www.consul.io/docs/agent/config/config-files#auto_config
|
|
[agent/consul/auto_config_endpoint.go]: https://github.com/hashicorp/consul/blob/main/agent/consul/auto_config_endpoint.go
|
|
[agent/auto-config]: https://github.com/hashicorp/consul/tree/main/agent/auto-config
|