Appcenter no longer starts, Docker no longer runs

Hi@all,
on a UCS member I have some time since sProblem that the appcenter does not start anymore because Docker.io does not run.

The file system is ext4 (not brtfs). In the logfile I find:

Dec 15 14:37:13 saturn systemd[1]: Starting Docker Socket for the API.
Dec 15 14:37:13 saturn systemd[1]: Listening on Docker Socket for the API.
Dec 15 14:37:13 saturn systemd[1]: Starting Docker Application Container Engine...
Dec 15 14:37:14 saturn dockerd[17242]: Status: unknown flag: --max-size
Dec 15 14:37:14 saturn dockerd[17242]: See 'dockerd --help'.
Dec 15 14:37:14 saturn dockerd[17242]: Usage:#011dockerd COMMAND
Dec 15 14:37:14 saturn dockerd[17242]: A self-sufficient runtime for containers.
Dec 15 14:37:14 saturn dockerd[17242]: Options:
Dec 15 14:37:14 saturn dockerd[17242]:       --add-runtime runtime                   Register an additional OCI compatible runtime (default [])
Dec 15 14:37:14 saturn dockerd[17242]:       --api-cors-header string                Set CORS headers in the Engine API
Dec 15 14:37:14 saturn dockerd[17242]:       --authorization-plugin list             Authorization plugins to load (default [])
Dec 15 14:37:14 saturn dockerd[17242]:       --bip string                            Specify network bridge IP
Dec 15 14:37:14 saturn dockerd[17242]:   -b, --bridge string                         Attach containers to a network bridge
Dec 15 14:37:14 saturn dockerd[17242]:       --cgroup-parent string                  Set parent cgroup for all containers
Dec 15 14:37:14 saturn dockerd[17242]:       --cluster-advertise string              Address or interface name to advertise
Dec 15 14:37:14 saturn dockerd[17242]:       --cluster-store string                  URL of the distributed storage backend
Dec 15 14:37:14 saturn dockerd[17242]:       --cluster-store-opt map                 Set cluster store options (default map[])
Dec 15 14:37:14 saturn dockerd[17242]:       --config-file string                    Daemon configuration file (default "/etc/docker/daemon.json")
Dec 15 14:37:14 saturn dockerd[17242]:       --containerd string                     Path to containerd socket
Dec 15 14:37:14 saturn dockerd[17242]:       --cpu-rt-period int                     Limit the CPU real-time period in microseconds
Dec 15 14:37:14 saturn dockerd[17242]:       --cpu-rt-runtime int                    Limit the CPU real-time runtime in microseconds
Dec 15 14:37:14 saturn dockerd[17242]:   -D, --debug                                 Enable debug mode
Dec 15 14:37:14 saturn dockerd[17242]:       --default-gateway ip                    Container default gateway IPv4 address
Dec 15 14:37:14 saturn dockerd[17242]:       --default-gateway-v6 ip                 Container default gateway IPv6 address
Dec 15 14:37:14 saturn dockerd[17242]:       --default-runtime string                Default OCI runtime for containers (default "runc")
Dec 15 14:37:14 saturn dockerd[17242]:       --default-ulimit ulimit                 Default ulimits for containers (default [])
Dec 15 14:37:14 saturn dockerd[17242]:       --disable-legacy-registry               Disable contacting legacy registries
Dec 15 14:37:14 saturn dockerd[17242]:       --dns list                              DNS server to use (default [])
Dec 15 14:37:14 saturn dockerd[17242]:       --dns-opt list                          DNS options to use (default [])
Dec 15 14:37:14 saturn dockerd[17242]:       --dns-search list                       DNS search domains to use (default [])
Dec 15 14:37:14 saturn dockerd[17242]:       --exec-opt list                         Runtime execution options (default [])
Dec 15 14:37:14 saturn dockerd[17242]:       --exec-root string                      Root directory for execution state files (default "/var/run/docker")
Dec 15 14:37:14 saturn dockerd[17242]:       --experimental                          Enable experimental features
Dec 15 14:37:14 saturn dockerd[17242]:       --fixed-cidr string                     IPv4 subnet for fixed IPs
Dec 15 14:37:14 saturn dockerd[17242]:       --fixed-cidr-v6 string                  IPv6 subnet for fixed IPs
Dec 15 14:37:14 saturn dockerd[17242]:   -g, --graph string                          Root of the Docker runtime (default "/var/lib/docker")
Dec 15 14:37:14 saturn dockerd[17242]:   -G, --group string                          Group for the unix socket (default "docker")
Dec 15 14:37:14 saturn dockerd[17242]:       --help                                  Print usage
Dec 15 14:37:14 saturn dockerd[17242]:   -H, --host list                             Daemon socket(s) to connect to (default [])
Dec 15 14:37:14 saturn dockerd[17242]:       --icc                                   Enable inter-container communication (default true)
Dec 15 14:37:14 saturn dockerd[17242]:       --init                                  Run an init in the container to forward signals and reap processes
Dec 15 14:37:14 saturn dockerd[17242]:       --init-path string                      Path to the docker-init binary
Dec 15 14:37:14 saturn dockerd[17242]:       --insecure-registry list                Enable insecure registry communication (default [])
Dec 15 14:37:14 saturn dockerd[17242]:       --ip ip                                 Default IP when binding container ports (default 0.0.0.0)
Dec 15 14:37:14 saturn dockerd[17242]:       --ip-forward                            Enable net.ipv4.ip_forward (default true)
Dec 15 14:37:14 saturn dockerd[17242]:       --ip-masq                               Enable IP masquerading (default true)
Dec 15 14:37:14 saturn dockerd[17242]:       --iptables                              Enable addition of iptables rules (default true)
Dec 15 14:37:14 saturn dockerd[17242]:       --ipv6                                  Enable IPv6 networking
Dec 15 14:37:14 saturn dockerd[17242]:       --label list                            Set key=value labels to the daemon (default [])
Dec 15 14:37:14 saturn dockerd[17242]:       --live-restore                          Enable live restore of docker when containers are still running
Dec 15 14:37:14 saturn dockerd[17242]:       --log-driver string                     Default driver for container logs (default "json-file")
Dec 15 14:37:14 saturn dockerd[17242]:   -l, --log-level string                      Set the logging level ("debug", "info", "warn", "error", "fatal") (default "info")
Dec 15 14:37:14 saturn systemd[1]: docker.service: Main process exited, code=exited, status=1/FAILURE
Dec 15 14:37:14 saturn dockerd[17242]:       --log-opt map                           Default log driver options for containers (default map[])
Dec 15 14:37:14 saturn dockerd[17242]:       --max-concurrent-downloads int          Set the max concurrent downloads for each pull (default 3)
Dec 15 14:37:14 saturn dockerd[17242]:       --max-concurrent-uploads int            Set the max concurrent uploads for each push (default 5)
Dec 15 14:37:14 saturn dockerd[17242]:       --metrics-addr string                   Set default address and port to serve the metrics api on
Dec 15 14:37:14 saturn dockerd[17242]:       --mtu int                               Set the containers network MTU
Dec 15 14:37:14 saturn dockerd[17242]:       --oom-score-adjust int                  Set the oom_score_adj for the daemon (default -500)
Dec 15 14:37:14 saturn dockerd[17242]:   -p, --pidfile string                        Path to use for daemon PID file (default "/var/run/docker.pid")
Dec 15 14:37:14 saturn dockerd[17242]:       --raw-logs                              Full timestamps without ANSI coloring
Dec 15 14:37:14 saturn dockerd[17242]:       --registry-mirror list                  Preferred Docker registry mirror (default [])
Dec 15 14:37:14 saturn dockerd[17242]:       --seccomp-profile string                Path to seccomp profile
Dec 15 14:37:14 saturn dockerd[17242]:       --selinux-enabled                       Enable selinux support
Dec 15 14:37:14 saturn dockerd[17242]:       --shutdown-timeout int                  Set the default shutdown timeout (default 15)
Dec 15 14:37:14 saturn dockerd[17242]:   -s, --storage-driver string                 Storage driver to use
Dec 15 14:37:14 saturn dockerd[17242]:       --storage-opt list                      Storage driver options (default [])
Dec 15 14:37:14 saturn dockerd[17242]:       --swarm-default-advertise-addr string   Set default address or interface for swarm advertised address
Dec 15 14:37:14 saturn dockerd[17242]:       --tls                                   Use TLS; implied by --tlsverify
Dec 15 14:37:14 saturn dockerd[17242]:       --tlscacert string                      Trust certs signed only by this CA (default "/root/.docker/ca.pem")
Dec 15 14:37:14 saturn dockerd[17242]:       --tlscert string                        Path to TLS certificate file (default "/root/.docker/cert.pem")
Dec 15 14:37:14 saturn dockerd[17242]:       --tlskey string                         Path to TLS key file (default "/root/.docker/key.pem")
Dec 15 14:37:14 saturn dockerd[17242]:       --tlsverify                             Use TLS and verify the remote
Dec 15 14:37:14 saturn dockerd[17242]:       --userland-proxy                        Use userland proxy for loopback traffic (default true)
Dec 15 14:37:14 saturn dockerd[17242]:       --userland-proxy-path string            Path to the userland proxy binary
Dec 15 14:37:14 saturn systemd[1]: Failed to start Docker Application Container Engine.
Dec 15 14:37:14 saturn dockerd[17242]:       --userns-remap string                   User/Group setting for user namespaces
Dec 15 14:37:14 saturn dockerd[17242]:   -v, --version                               Print version information and quit
Dec 15 14:37:14 saturn dockerd[17242]: Run 'dockerd COMMAND --help' for more information on a command.
Dec 15 14:37:14 saturn dockerd[17242]: , Code: 125
Dec 15 14:37:14 saturn systemd[1]: docker.service: Unit entered failed state.
Dec 15 14:37:14 saturn systemd[1]: docker.service: Failed with result 'exit-code'.

How do I get Docker to run again?

with bst
sven