journalctl

# Check the logs for more information to see why the api-server is not running and how to fix the problem:
journalctl -xn --unit kubelet.service

# most recent 50 log entries from a nginx service
journalctl -fn 50 -u nginx

# If you want to see the logs of the service,
journalctl -f -u mms_agent.service

# If any error happen
journalctl -u restart-coordinator.service

# Find OOM issues in kubernetes
journalctl -u kubelet | grep -i "oom"

# Terminal History:
To get name of the history file, type: echo "$HISTFILE"
history | grep -E 'du|df|wc'

# Check disk usage by journal
journalctl --disk-usage

OTHER:
sudo dmesg | grep -i -E 'error|warn|failed'
journalctl --since "2020-06-04 10:42:00" --until "2020-06-07 10:42:00"
journalctl -u kubelet --since 2m