As I suspected, the cronjob is then not executed and with every container restart or update the cronjob is reinitialized.
Today the cronjob ran through, however, this also does not work correctly, the certs were not renewed:
ofelia-mailcow_1 | 2021-06-21T03:03:26.101795969Z 2021-06-21T03:03:26.101Z common.go:125 ▶ NOTICE [Job "ejabberd_certs" (9be50e9eb360)] Started - /sbin/su-exec ejabberd /home/ejabberd/bin/ejabberdctl --node ejabberd@${MAILCOW_HOSTNAME} request-certificate all
ofelia-mailcow_1 | 2021-06-21T03:03:27.924598315Z 2021-06-21T03:03:27.924Z common.go:121 ▶ ERROR [Job "ejabberd_certs" (9be50e9eb360)] StdOut: Failed RPC connection to the node 'ejabberd@${MAILCOW_HOSTNAME}': nodedown
ofelia-mailcow_1 | 2021-06-21T03:03:27.924639850Z Commands to start an ejabberd node:
ofelia-mailcow_1 | 2021-06-21T03:03:27.924646129Z start Start an ejabberd node in server mode
ofelia-mailcow_1 | 2021-06-21T03:03:27.924653236Z debug Attach an interactive Erlang shell to a running ejabberd node
ofelia-mailcow_1 | 2021-06-21T03:03:27.924660623Z iexdebug Attach an interactive Elixir shell to a running ejabberd node
ofelia-mailcow_1 | 2021-06-21T03:03:27.924667645Z live Start an ejabberd node in live (interactive) mode
ofelia-mailcow_1 | 2021-06-21T03:03:27.924674679Z iexlive Start an ejabberd node in live (interactive) mode, within an Elixir shell
ofelia-mailcow_1 | 2021-06-21T03:03:27.924681982Z foreground Start an ejabberd node in server mode (attached)
ofelia-mailcow_1 | 2021-06-21T03:03:27.924695651Z Optional parameters when starting an ejabberd node:
ofelia-mailcow_1 | 2021-06-21T03:03:27.924702904Z --config-dir dir Config ejabberd: /home/ejabberd/conf
ofelia-mailcow_1 | 2021-06-21T03:03:27.924710045Z --config file Config ejabberd: /home/ejabberd/conf/ejabberd.yml
ofelia-mailcow_1 | 2021-06-21T03:03:27.924717239Z --ctl-config file Config ejabberdctl: /home/ejabberd/conf/ejabberdctl.cfg
ofelia-mailcow_1 | 2021-06-21T03:03:27.924724696Z --logs dir Directory for logs: /home/ejabberd/logs
ofelia-mailcow_1 | 2021-06-21T03:03:27.924731845Z --spool dir Database spool dir: /home/ejabberd/database/ejabberd@${MAILCOW_HOSTNAME}
ofelia-mailcow_1 | 2021-06-21T03:03:27.924739454Z --node nodename ejabberd node name: ejabberd@${MAILCOW_HOSTNAME}
ofelia-mailcow_1 | 2021-06-21T03:03:27.924753107Z 2021-06-21T03:03:27.924Z common.go:121 ▶ ERROR [Job "ejabberd_certs" (9be50e9eb360)] Finished in "1.822136097s", failed: true, skipped: false, error: error