DroveDNS

Name

drovedns - DNS answers for apps runing on drove

Description

The plugins can be used to implement service discovery through dns for apps running on drove. Plugin answers with SRV record for container discovery, optionally forward plugin can be used to add A record of drove-gateway

Compilation

This package will always be compiled as part of CoreDNS and not in a standalone way. It will require you to use go get or as a dependency on plugin.cfg.

The manual will have more information about how to configure and extend the server with external plugins.

A simple way to consume this plugin, is by adding the following on plugin.cfg, and recompile it as detailed on coredns.io.

drove:github.com/PhonePe/coredns-drove

Put this early in the plugin list, so that drovedns is executed before any of the other plugins.

After this you can compile coredns by:

go generate
go build

Or you can instead use make:

make

Syntax

drovedns {
  endpoint [URL]
  accesstoken [TOKEN]
  user_pass [USERNAME] [PASSWORD]
  skip_ssl_check
}

• URL - Comma seperated list of drove controllers
• TOKEN - In case drove controllers are using bearer auth Complete Authorization header "Bearer ..."
• user pass - In case drove is using basic auth
• skip_ssl_check - To skip client side ssl certificate validation

Ready

This plugin reports readiness to the ready plugin. It will be immediately ready.

Metrics

If monitoring is enabled (via the prometheus plugin) then the following metrics are exported:

• coredns_drove_controller_health{host} - Exports the health of controller at any given point The following are client level metrics to monitor apiserver request latency & status codes. verb identifies the apiserver request type and host denotes the apiserver endpoint.
• coredns_drove_sync_total - captures total app syncs from drove.
• coredns_drove_sync_failure - captures failed app syncs from drove.
• coredns_drove_api_total{status_code, method, host} - captures drove request grouped by status_code, method & host.

Examples

In this configuration, we resolve queries through the plugin and enrich the answers with A record from servers listed in local resolv.conf

example.drove.gateway.com {
  drovedns {
    endpoint "http://drove-control001.example.com:8080,http://drove-control002.example.com:8080"
    accesstoken "Bearer foo"
  }
  forward . /etc/resolv.conf
}

Docker

Docker image containing coredns compiled with the plugin are available on ghcr.

docker run  -p1053:1053/udp -p1053:1053 \
    -e DROVE_ENDPOINT="https://drovecontrol001.exmaple.com:8080,https://drovecontrol002.exmaple.com:8080,https://drovecontrol003.exmaple.com:8080"  \
    -e DROVE_USERNAME="<USERNAME>" -e DROVE_PASSWORD="<PASSWORD>"  \
    -it ghcr.io/phonepe/coredns-drove:<VERSION>

Alternatively you can provide your own Corefile

docker run  -p1053:1053/udp -p1053:1053 \
    -v /path/to/Corefile:/opt/Corefile  \
    -it ghcr.io/phonepe/coredns-drove:<VERSION>

Also See

See the manual.