https://github.com/fredex42/pgismaster
Indicate if a postgres server is a master or slave
https://github.com/fredex42/pgismaster
failover high-availability keepalived postgres postgresql
Last synced: 3 months ago
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Indicate if a postgres server is a master or slave
- Host: GitHub
- URL: https://github.com/fredex42/pgismaster
- Owner: fredex42
- Created: 2019-10-14T15:28:06.000Z (over 5 years ago)
- Default Branch: master
- Last Pushed: 2019-11-16T12:15:00.000Z (over 5 years ago)
- Last Synced: 2024-04-24T07:53:44.543Z (about 1 year ago)
- Topics: failover, high-availability, keepalived, postgres, postgresql
- Language: Go
- Homepage:
- Size: 4.88 KB
- Stars: 2
- Watchers: 1
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# pgismaster
## What is it?
pgismaster is a very simple little program designed to indicate to a process like keepalived whether
a given postgres server is a master or a standby.
This is done by checking the internal flag "pg_is_in_recovery();"; an active slave is permanently in a recovery
state and a master is not.
- If run on a slave, then a message is printed to indicate that it is a slave and an exit status of 1 is returned.
- If run on a master, then a message is printed to indicate that it is a master and an exit status of 0 is returned.
This allows it to be run in the "script" parameter of keepalived to allow only a master to assert a VIP.
## How do I run it?
Simply grab the compiled executable and copy it to your server. Then, call it in your script or config file.
For example, in `keepalived.conf`:
```
global_defs {
enable_script_security
script_user postgres ###server is configured to allow local access here
}
vrrp_script chk_postgres { # Requires keepalived-1.1.13
script "/usr/local/bin/pgismaster"
interval 10 # check every 10 seconds
fall 2 # require 2 failures for KO
rise 2 # require 2 successes for OK
}
vrrp_instance VI_1 {
interface ens192
virtual_router_id 42
priority 150
state MASTER
virtual_ipaddress {
1.2.3.4
}
track_script {
chk_postgres
}
}
```
Or just run from the commandline:
```
$ /usr/local/bin/pgismaster
2019/10/14 16:45:31 pgismaster, Andy Gallagher 2019. See https://github.com/fredex42/pgismaster for details.
2019/10/14 16:45:31 Server is a standby
$ echo $?
1
```
## How do I compile it?
You'll need Go 1.11 or later available to compile (but not to run).
You can either head over to https://golang.org/doc/install#install or use docker (e.g. `docker run --rm golang:1.12-alpine3.9`)
Check out the sources: `git clone https://github.com/fredex42/pgismaster`
Compile it for Linux: `GOOS=linux go build`
Or for Windows: `GOOS=windows go build`
Or for Mac: `GOOS=darwin go build`
etc.
Dependencies are managed via go modules, so any required libraries should be automatically downloaded and compiled in the `build` command.
See the official Go documentation for cross-compilation options.