httpwsrep
HTTP status codes for galera cluster
This helps to check the galera cluster using HAProxy - option httpchk
which queries the galera node and gets its current state from:
SHOW STATUS LIKE 'wsrep_local_state';
if wsrep_local_state == 4 it will return HTTP 200 OK, otherwise
HTTP 503 Service Unavailable
The posible values for wsrep_local_state are:
| Num | Comment | Description |
|---|---|---|
| 1 | Joining | Node is joining the cluster |
| 2 | Donor/Desynced | Node is the donor to the node joining the cluster |
| 3 | Joined | Node has joined the cluster |
| 4 | Synced | Node is synced with the cluster |
HAProxy example
backend galera
mode tcp
option httpchk
default-server check port 9200
server node0 10.0.0.1:3306
server node1 10.0.0.2:3306
server node2 10.0.0.3:3306
httpwsrep
You need to run httpwsrep in each galera node preferably using a supervisor,
for example if using immortal you could create
/usr/local/etc/immortal/httpwsrep.yml with something like this:
cmd: /path/to/httpwsrep
env:
DSN: mysql://haproxy@tcp(10.0.0.1:3306)/
log:
file: /var/log/httpwsrep.log
a valid mysql user needs to be created, in this case the user is
haproxy
By default port 9200 is used but if required can change it using option --port
