failed to start daemon: pid file found, ensure docker is not running or delete /var/run/docker.pid code example
Example 1: failed to start daemon: pid file found, ensure docker is not running or delete /var/run/docker.pid
sudo rm /var/run/docker.pid
systemctl start docker
Example 2: failed to start daemon: pid file found, ensure docker is not running or delete /var/run/docker.pid
$ rm -rf /var/snap/docker/179/run/docker.pid
$ systemctl start docker