Dockerfile and Dockerfile.citus

You can run Patroni in a docker container using these Dockerfiles

They are meant in aiding development of Patroni and quick testing of features and not a production-worthy!

docker build -t patroni .
docker build -f Dockerfile.citus -t patroni-citus .

Examples

Standalone Patroni

docker run -d patroni

Three-node Patroni cluster

In addition to three Patroni containers the stack starts three containers with etcd (forming a three-node cluster), and one container with haproxy. The haproxy listens on ports 5000 (connects to the primary) and 5001 (does load-balancing between healthy standbys).

Example session:

$ docker compose up -d
✔ Network patroni_demo     Created
✔ Container demo-etcd1     Started
✔ Container demo-haproxy   Started
✔ Container demo-patroni1  Started
✔ Container demo-patroni2  Started
✔ Container demo-patroni3  Started
✔ Container demo-etcd2     Started
✔ Container demo-etcd3     Started

$ docker ps
CONTAINER ID   IMAGE     COMMAND                  CREATED          STATUS          PORTS                                                           NAMES
a37bcec56726   patroni   "/bin/sh /entrypoint…"   15 minutes ago   Up 15 minutes                                                                   demo-etcd3
034ab73868a8   patroni   "/bin/sh /entrypoint…"   15 minutes ago   Up 15 minutes                                                                   demo-patroni2
03837736f710   patroni   "/bin/sh /entrypoint…"   15 minutes ago   Up 15 minutes                                                                   demo-patroni3
22815c3d85b3   patroni   "/bin/sh /entrypoint…"   15 minutes ago   Up 15 minutes                                                                   demo-etcd2
814b4304d132   patroni   "/bin/sh /entrypoint…"   15 minutes ago   Up 15 minutes   0.0.0.0:5000-5001->5000-5001/tcp, :::5000-5001->5000-5001/tcp   demo-haproxy
6375b0ba2d0a   patroni   "/bin/sh /entrypoint…"   15 minutes ago   Up 15 minutes                                                                   demo-patroni1
aef8bf3ee91f   patroni   "/bin/sh /entrypoint…"   15 minutes ago   Up 15 minutes                                                                   demo-etcd1

$ docker logs demo-patroni1
2023-11-21 09:04:33,547 INFO: Selected new etcd server http://172.29.0.3:2379
2023-11-21 09:04:33,605 INFO: Lock owner: None; I am patroni1
2023-11-21 09:04:33,693 INFO: trying to bootstrap a new cluster
...
2023-11-21 09:04:34.920 UTC [43] LOG:  starting PostgreSQL 15.5 (Debian 15.5-1.pgdg120+1) on x86_64-pc-linux-gnu, compiled by gcc (Debian 12.2.0-14) 12.2.0, 64-bit
2023-11-21 09:04:34.921 UTC [43] LOG:  listening on IPv4 address "0.0.0.0", port 5432
2023-11-21 09:04:34,922 INFO: postmaster pid=43
2023-11-21 09:04:34.922 UTC [43] LOG:  listening on Unix socket "/var/run/postgresql/.s.PGSQL.5432"
2023-11-21 09:04:34.925 UTC [47] LOG:  database system was shut down at 2023-11-21 09:04:34 UTC
2023-11-21 09:04:34.928 UTC [43] LOG:  database system is ready to accept connections
localhost:5432 - accepting connections
localhost:5432 - accepting connections
2023-11-21 09:04:34,938 INFO: establishing a new patroni heartbeat connection to postgres
2023-11-21 09:04:34,992 INFO: running post_bootstrap
2023-11-21 09:04:35,004 WARNING: User creation via "bootstrap.users" will be removed in v4.0.0
2023-11-21 09:04:35,009 WARNING: Could not activate Linux watchdog device: Can't open watchdog device: [Errno 2] No such file or directory: '/dev/watchdog'
2023-11-21 09:04:35,189 INFO: initialized a new cluster
2023-11-21 09:04:35,328 INFO: no action. I am (patroni1), the leader with the lock
2023-11-21 09:04:43,824 INFO: establishing a new patroni restapi connection to postgres
2023-11-21 09:04:45,322 INFO: no action. I am (patroni1), the leader with the lock
2023-11-21 09:04:55,320 INFO: no action. I am (patroni1), the leader with the lock
...

$ docker exec -ti demo-patroni1 bash
postgres@patroni1:~$ patronictl list
+ Cluster: demo (7303838734793224214) --------+----+-----------+
| Member   | Host       | Role    | State     | TL | Lag in MB |
+----------+------------+---------+-----------+----+-----------+
| patroni1 | 172.29.0.2 | Leader  | running   |  1 |           |
| patroni2 | 172.29.0.6 | Replica | streaming |  1 |         0 |
| patroni3 | 172.29.0.5 | Replica | streaming |  1 |         0 |
+----------+------------+---------+-----------+----+-----------+

postgres@patroni1:~$ etcdctl get --keys-only --prefix /service/demo
/service/demo/config
/service/demo/initialize
/service/demo/leader
/service/demo/members/patroni1
/service/demo/members/patroni2
/service/demo/members/patroni3
/service/demo/status

postgres@patroni1:~$ etcdctl member list
2bf3e2ceda5d5960, started, etcd2, http://etcd2:2380, http://172.29.0.3:2379
55b3264e129c7005, started, etcd3, http://etcd3:2380, http://172.29.0.7:2379
acce7233f8ec127e, started, etcd1, http://etcd1:2380, http://172.29.0.8:2379


postgres@patroni1:~$ exit

$ docker exec -ti demo-haproxy bash
postgres@haproxy:~$ psql -h localhost -p 5000 -U postgres -W
Password: postgres
psql (15.5 (Debian 15.5-1.pgdg120+1))
Type "help" for help.

postgres=# SELECT pg_is_in_recovery();
 pg_is_in_recovery
───────────────────
 f
(1 row)

postgres=# \q

postgres@haproxy:~$ psql -h localhost -p 5001 -U postgres -W
Password: postgres
psql (15.5 (Debian 15.5-1.pgdg120+1))
Type "help" for help.

postgres=# SELECT pg_is_in_recovery();
 pg_is_in_recovery
───────────────────
 t
(1 row)

Citus cluster

The stack starts three containers with etcd (forming a three-node etcd cluster), seven containers with Patroni+PostgreSQL+Citus (three coordinator nodes, and two worker clusters with two nodes each), and one container with haproxy. The haproxy listens on ports 5000 (connects to the coordinator primary) and 5001 (does load-balancing between worker primary nodes).