Add python3-systemd as Debian package dependency

[gmemstr]

What happened?

When upgrading to 4.1.0 on Debian through the PGDG repository, the Patroni service failed to restart. After some research, I cam across https://github.com/patroni/patroni/issues/3459, which led me to find the commit introducing the new systemd integration. It took me a while to realise the python3-systemd package was not automatically installed, so Patroni was never signaling to systemd that is was ready.

How can we reproduce it (as minimally and precisely as possible)?

• Install Patroni from PGDG on Debian Trixie
• Restart service

What did you expect to happen?

• Service restarts normally.

Patroni/PostgreSQL/DCS version

• Patroni version: 4.1.0
• PostgreSQL version: 18.0-1.pgdg13+3
• DCS (and its version): etcd (3.6.5)

Patroni configuration file

scope: homelab_cluster
name: "236.pgdb.gmem.ca"

log:
  traceback_level: INFO
  level: DEBUG
  dir: /var/log/patroni/
  file_num: 5

restapi:
  listen: 0.0.0.0:8008
  connect_address: "192.168.50.236:8008"

etcd3:
  protocol: http
  hosts:
    - "192.168.50.236:2379"
    - "192.168.50.237:2379"
    - "192.168.50.238:2379"

bootstrap:
  dcs:
    ttl: 30
    loop_wait: 10
    retry_timeout : 10
    maximum_lag_on_failover: 1048576
    postgresql:
      use_pg_rewind: true
      use_slots: true

  initdb:
  - encoding: UTF8
  - data-checksums

  pg_hba:
  - host all all 192.168.50.0/24 scram-sha-256
  - host all all 192.168.50.0/24 md5
  - host replication patroni_replication 192.168.50.232/29 md5

postgresql:
  listen: "192.168.50.236,192.168.50.233:5432"
  connect_address: "192.168.50.236:5432"
  data_dir: /var/lib/postgresql/18/main/
  config_dir: /etc/postgresql/18/main/
  bin_dir: /usr/lib/postgresql/18/bin
  authentication:
    replication:
      username: patroni_replication
      password: [ removed ]
    superuser:
      username: patroni_superuser
      password: [ removed ]
    rewind:
        username: patroni_rewind
        password: [ removed ]
  parameters:
    io_method: worker
    io_workers: 3
    # DB Version: 18
    # OS Type: linux
    # DB Type: mixed
    # Total Memory (RAM): 1 GB
    # CPUs num: 2
    # Connections num: 100
    # Data Storage: ssd
    max_connections: 100
    shared_buffers: 256MB
    effective_cache_size:  768MB
    maintenance_work_mem:  64MB
    checkpoint_completion_target:  0.9
    wal_buffers:  7864kB
    default_statistics_target:  100
    random_page_cost:  1.1
    effective_io_concurrency:  200
    work_mem:  1213kB
    huge_pages:  off
    min_wal_size: 1GB
    max_wal_size: 4GB

patronictl show-config

loop_wait: 10
maximum_lag_on_failover: 1048576
postgresql:
  parameters:
    wal_keep_segments: 200
    wal_keep_size: 512MB
  use_pg_rewind: true
  use_slots: true
retry_timeout: 10
ttl: 30

Patroni log files

None

PostgreSQL log files

None

Have you tried to use GitHub issue search?

• [x] Yes

Anything else we need to know?

No response

[CyberDem0n]

cc @mbanck