Galera Health Check

HTTP Server tha reports the health status of a galera cluster nocde

Server settings can be configured via parameters or via configuration. Parameters will take precedence over configuration settings.

Database settings can only be configured via configuration.

Usage

Create an appropriate configuration.

To Start:

./galera-health

The output given should look like:

INFO[0000] Started on :33060

Parameters

The script exporter has the following command line arguments:

Usage of script_exporter
  -V	show version information
  -c string
    	config file in yaml format (default "/etc/default/galera-health")
  -h string
    	ip used for listening, leave empty for all available IP addresses
  -p int
    	port used for listening (default 33060)
  -v	show verbose output

The -h and -p setting will overrule the settings made in the config files for these specific options.

Configuration

The configuration files are made in yaml format.

Default the config files is /etc/default/galera-health.

key	description
host	ip used for listening, leave empty for all available IP addresses
port	port used for listening (default 33060)
db	database config options
available_when_donor	should being a donor be considered health or unhealth, when set to true donors are concidered health (default true)

Database sub options

key	description
host	ip address or hostname of the database server (default localhost)
port	port to use when connecting to the database server (default 3306)
username	useranem to connect to the database (default monitoring)
password	password for the user to connect to the database

Example:

---
host: 127.0.0.1
port: 80
db:
    host: localhost
    port: 3306
    username: root
    password: TopSecret!
available_when_donor: true

Endpoints

This server exposes a single GET endpoint on /

HTTP Results

HTTP 200 OK is returned when the database server is healthy HTTP 503 Service Unavailable is returned when the server is unhealth

THe result body displays additional information on the result

HTTP 200 OK messages

message	description
not a cluster node	server is health, but not a galera cluster node
donor	returned when wsrep_local_state equals `2` and `available_when_donor` is configured to `true`
synced	returned when wsrep_local_state equals `4`

HTTP 503 Service Unavailable messages

message	description
wsrep_on not set	variable `wsrep_on` is not set on the server
required variables not set	status wsrep_ready, status wsrep_connected or status wsrep_local_state are not set on the server, this should not happen when wsrep_on = On
not ready	returned when wsrep_ready equals `off`
not connected	returned when wsrep_connected equals `off`
joining	returned when wsrep_local_state equals `1`
donor	returned when wsrep_local_state equals `2` and `available_when_donor` is configured to `false`
joined	returned when wsrep_local_state equals `3`
Unrecognized state: {str}	returned when wsrep_local_state anything other than 1, 2, 3 or 4
connection refused	returned when no connection to the configured database server could be made
{error message}	returned when an error occurs that is not otherwise defined

Developing

If you want to contribute to this project please follow these guidelines:

Script Exporter is build in Golang
Use style guides as described in .editorconfig
Changes in features should be reflected in this README.md
Changes should be reflected into the CHANGELOG.md

The maintainers

Bump the VERSION file if a release is needed

Building

To create a working binary use:

git clone git@github.com:Team-MostWanted/galera-health.git
cd galera-health
make

This creates a binary in the ./build folder. Look at the Build options section for more build options.

Make options

The targets used by default are:

freebsd/amd64
darwin/amd64
darwin/arm64
linux/amd64
linux/arm64
windows/amd64

Use make <command> TARGETS=<os>/<arch> to execute make with your own OS and Architecture, e.g. make build TARGETS=freebsd/arm64.

target	description
version	retrieve and display the version from the CHANGELOG.md
test	use `go test` to execute the unit test and create a coverage report `./build/test-coverage.out`
build	build the binary for every OS and Arch stated
dist-check	validations performed to see if the codebase is ready for a release, on default this will skipped unless performed on the acceptance or master branch
dist-create	create tar.gz files in `./dist` for all targets using the binaries from `./build`
dist	perform a clean, dist-check build and dist-create
update-dependencies	update go version and update dependencies, makes sure everything is tiday, and add a line to the changelog
update	perform a clean, update-dependencies and a test
clean	clean the build and dist directories

TODO

add tests

Changelog

All notable changes for the Galera Health Check can be found in CHANGELOG.md.