The well-known Linux distribution Ubuntu provides a strong mechanism for handling services. These services are background programs that are either manually invoked or launched at boot. They administer logging, network administration, and other functions that are essential to the system's operation.
It is essential for webmasters and administrators to comprehend how to handle these services. An issue-ridden server or one that runs smoothly can be determined by one's ability to list, manage, and troubleshoot these services.
Systemd is now the default init system on Ubuntu. This implies that systemd is in charge of controlling system processes and bootstrapping the user space. Understanding this change is crucial before beginning to use commands, as the majority of service management commands will centre around the systemctl utility provided by systemd.
Systemd is the first process to launch on your Ubuntu server. It is in charge of starting up several services, including the SSH daemon and network manager. Consider systemd to be the system administrator in charge of all other services.
List All Services
Use the following command to list all services, whether they are failed, inactive, or active: sudo systemctl list-units --type=service --all
This command offers a detailed list that displays each service's current status.
suyi@suyi:~$ sudo systemctl list-units --type=service --all
UNIT LOAD ACTIVE SUB DESCRIPTION
apparmor.service loaded active exited Load AppArmor profiles
apport-autoreport.service loaded inactive dead Process error reports when automatic reporting is enabled
apport.service loaded active exited LSB: automatic crash report generation
apt-daily-upgrade.service loaded inactive dead Daily apt upgrade and clean activities
apt-daily.service loaded inactive dead Daily apt download activities
● auditd.service not-found inactive dead auditd.service
blk-availability.service loaded active exited Availability of block devices
cloud-config.service loaded active exited Apply the settings specified in cloud-config
cloud-final.service loaded active exited Execute cloud user/final scripts
cloud-init-hotplugd.service loaded inactive dead cloud-init hotplug hook daemon
cloud-init-local.service loaded active exited Initial cloud-init job (pre-networking)
cloud-init.service loaded active exited Initial cloud-init job (metadata service crawler)
● connman.service not-found inactive dead connman.service
● console-screen.service not-found inactive dead console-screen.service
console-setup.service loaded active exited Set console font and keymap
containerd.service loaded active running containerd container runtime
cron.service loaded active running Regular background program processing daemon
dbus.service loaded active running D-Bus System Message Bus
● display-manager.service not-found inactive dead display-manager.service
dm-event.service loaded inactive dead Device-mapper event daemon
dmesg.service loaded inactive dead Save initial kernel messages after boot
docker.service loaded active running Docker Application Container Engine
dpkg-db-backup.service loaded inactive dead Daily dpkg database backup service
e2scrub_all.service loaded inactive dead Online ext4 Metadata Check for All Filesystems
e2scrub_reap.service loaded inactive dead Remove Stale Online ext4 Metadata Check Snapshots
emergency.service loaded inactive dead Emergency Shell
● fcoe.service not-found inactive dead fcoe.service
finalrd.service loaded active exited Create final runtime dir for shutdown pivot root
● firewalld.service not-found inactive dead firewalld.service
fstrim.service loaded inactive dead Discard unused blocks on filesystems from /etc/fstab
fwupd-refresh.service loaded inactive dead Refresh fwupd metadata and update motd
getty-static.service loaded inactive dead getty on tty2-tty6 if dbus and logind are not available
getty@tty1.service loaded active running Getty on tty1
grub-common.service loaded inactive dead Record successful boot for GRUB
grub-initrd-fallback.service loaded inactive dead GRUB failed boot detection
● hv_kvp_daemon.service not-found inactive dead hv_kvp_daemon.service
irqbalance.service loaded active running irqbalance daemon
● iscsi-shutdown.service not-found inactive dead iscsi-shutdown.service
iscsid.service loaded inactive dead iSCSI initiator daemon (iscsid)
● kbd.service not-found inactive dead kbd.service
keyboard-setup.service loaded active exited Set the console keyboard layout
kmod-static-nodes.service loaded active exited Create List of Static Device Nodes
logrotate.service loaded inactive dead Rotate log files
● lvm2-activation-early.service not-found inactive dead lvm2-activation-early.service
● lvm2-activation.service not-found inactive dead lvm2-activation.service
lvm2-lvmpolld.service loaded inactive dead LVM2 poll daemon
lvm2-monitor.service loaded active exited Monitoring of LVM2 mirrors, snapshots etc. using dmeventd or progress polling
lvm2-pvscan@252:3.service loaded active exited LVM event activation on device 252:3
lxd-agent.service loaded inactive dead LXD - agent
man-db.service loaded inactive dead Daily man-db regeneration
ModemManager.service loaded active running Modem Manager
modprobe@configfs.service loaded inactive dead Load Kernel Module configfs
modprobe@drm.service loaded inactive dead Load Kernel Module drm
modprobe@efi_pstore.service loaded inactive dead Load Kernel Module efi_pstore
modprobe@fuse.service loaded inactive dead Load Kernel Module fuse
motd-news.service loaded inactive dead Message of the Day
multipathd.service loaded active running Device-Mapper Multipath Device Controller
netplan-ovs-cleanup.service loaded inactive dead OpenVSwitch configuration for cleanup
networkd-dispatcher.service loaded active running Dispatcher daemon for systemd-networkd
● networking.service not-found inactive dead networking.service
● NetworkManager.service not-found inactive dead NetworkManager.service
ntp-systemd-netif.service loaded inactive dead ntp-systemd-netif.service
ntp.service loaded active running Network Time Service
open-iscsi.service loaded inactive dead Login to default iSCSI targets
open-vm-tools.service loaded inactive dead Service for virtual machines hosted on VMware
● ovsdb-server.service not-found inactive dead ovsdb-server.service
plymouth-quit-wait.service loaded active exited Hold until boot process finishes up
plymouth-quit.service loaded active exited Terminate Plymouth Boot Screen
plymouth-read-write.service loaded active exited Tell Plymouth To Write Out Runtime Data
plymouth-start.service loaded inactive dead Show Plymouth Boot Screen
polkit.service loaded active running Authorization Manager
pollinate.service loaded inactive dead Pollinate to seed the pseudo random number generator
● rbdmap.service not-found inactive dead rbdmap.service
rc-local.service loaded inactive dead /etc/rc.local Compatibility
rescue.service loaded inactive dead Rescue Shell
rsyslog.service loaded active running System Logging Service
secureboot-db.service loaded inactive dead Secure Boot updates for DB and DBX
serial-getty@ttyS0.service loaded active running Serial Getty on ttyS0
setvtrgb.service loaded active exited Set console scheme
snap.lxd.activate.service loaded inactive dead Service for snap application lxd.activate
snap.lxd.daemon.service loaded inactive dead Service for snap application lxd.daemon
snap.lxd.user-daemon.service loaded inactive dead Service for snap application lxd.user-daemon
● snapd.aa-prompt-listener.service not-found inactive dead snapd.aa-prompt-listener.service
snapd.apparmor.service loaded active exited Load AppArmor profiles managed internally by snapd
snapd.autoimport.service loaded inactive dead Auto import assertions from block devices
snapd.core-fixup.service loaded inactive dead Automatically repair incorrect owner/permissions on core devices
snapd.failure.service loaded inactive dead Failure handling of the snapd snap
snapd.recovery-chooser-trigger.service loaded inactive dead Wait for the Ubuntu Core chooser trigger
snapd.seeded.service loaded active exited Wait until snapd is fully seeded
snapd.service loaded active running Snap Daemon
snapd.snap-repair.service loaded inactive dead Automatically fetch and run repair assertions
ssh.service loaded active running OpenBSD Secure Shell server
● sshd-keygen.service not-found inactive dead sshd-keygen.service
systemd-ask-password-console.service loaded inactive dead Dispatch Password Requests to Console
systemd-ask-password-plymouth.service loaded inactive dead Forward Password Requests to Plymouth
systemd-ask-password-wall.service loaded inactive dead Forward Password Requests to Wall
systemd-binfmt.service loaded active exited Set Up Additional Binary Formats
systemd-boot-system-token.service loaded inactive dead Store a System Token in an EFI Variable
systemd-fsck-root.service loaded inactive dead File System Check on Root Device
systemd-fsck@dev-disk-by\x2duuid-30683743\x2dc712\x2d4f97\x2d984a\x2d1113c82c48c6.service loaded active exited File System Check on /dev/disk/by-uuid/30683743-c712-4f97-984a-1113c82c48c6
systemd-fsckd.service loaded inactive dead File System Check Daemon to report status
● systemd-hwdb-update.service not-found inactive dead systemd-hwdb-update.service
systemd-initctl.service loaded inactive dead initctl Compatibility Daemon
systemd-journal-flush.service loaded active exited Flush Journal to Persistent Storage
systemd-journald.service loaded active running Journal Service
systemd-logind.service loaded active running User Login Management
systemd-machine-id-commit.service loaded inactive dead Commit a transient machine-id on disk
systemd-modules-load.service loaded active exited Load Kernel Modules
systemd-networkd-wait-online.service loaded active exited Wait for Network to be Configured
systemd-networkd.service loaded active running Network Configuration
systemd-pstore.service loaded inactive dead Platform Persistent Storage Archival
systemd-quotacheck.service loaded inactive dead File System Quota Check
systemd-random-seed.service loaded active exited Load/Save Random Seed
systemd-remount-fs.service loaded active exited Remount Root and Kernel File Systems
systemd-resolved.service loaded active running Network Name Resolution
systemd-rfkill.service loaded inactive dead Load/Save RF Kill Switch Status
systemd-sysctl.service loaded active exited Apply Kernel Variables
systemd-sysusers.service loaded active exited Create System Users
● systemd-timesyncd.service masked inactive dead systemd-timesyncd.service
systemd-tmpfiles-clean.service loaded inactive dead Cleanup of Temporary Directories
systemd-tmpfiles-setup-dev.service loaded active exited Create Static Device Nodes in /dev
systemd-tmpfiles-setup.service loaded active exited Create Volatile Files and Directories
systemd-udev-trigger.service loaded active exited Coldplug All udev Devices
systemd-udevd.service loaded active running Rule-based Manager for Device Events and Files
● systemd-update-done.service not-found inactive dead systemd-update-done.service
systemd-update-utmp-runlevel.service loaded inactive dead Record Runlevel Change in UTMP
systemd-update-utmp.service loaded active exited Record System Boot/Shutdown in UTMP
systemd-user-sessions.service loaded active exited Permit User Sessions
● systemd-vconsole-setup.service not-found inactive dead systemd-vconsole-setup.service
thermald.service loaded inactive dead Thermal Daemon Service
● ua-auto-attach.service not-found inactive dead ua-auto-attach.service
ua-reboot-cmds.service loaded inactive dead Ubuntu Pro reboot cmds
ua-timer.service loaded inactive dead Ubuntu Pro Timer for running repeated jobs
● ubuntu-advantage-cloud-id-shim.service not-found inactive dead ubuntu-advantage-cloud-id-shim.service
ubuntu-advantage.service loaded inactive dead Ubuntu Pro Background Auto Attach
udisks2.service loaded active running Disk Manager
ufw.service loaded active exited Uncomplicated firewall
unattended-upgrades.service loaded active running Unattended Upgrades Shutdown
update-notifier-download.service loaded inactive dead Download data for packages that failed at package install time
update-notifier-motd.service loaded inactive dead Check to see whether there is a new version of Ubuntu available
user-runtime-dir@1000.service loaded active exited User Runtime Directory /run/user/1000
user@1000.service loaded active running User Manager for UID 1000
uuidd.service loaded active running Daemon for generating UUIDs
vgauth.service loaded inactive dead Authentication service for virtual machines hosted on VMware
● zfs-mount.service not-found inactive dead zfs-mount.service
LOAD = Reflects whether the unit definition was properly loaded.
ACTIVE = The high-level unit activation state, i.e. generalization of SUB.
SUB = The low-level unit activation state, values depend on unit type.
145 loaded units listed.
To show all installed unit files use 'systemctl list-unit-files'.
Status of Service by Name
Use the following to find out the current state of a particular service: sudo systemctl status <Name of the service>
suyi@suyi:~$ sudo systemctl status docker
● docker.service - Docker Application Container Engine
Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: enabled)
Active: active (running) since Sun 2024-09-15 22:40:08 UTC; 3h 40min ago
TriggeredBy: ● docker.socket
Docs: https://docs.docker.com
Main PID: 849 (dockerd)
Tasks: 10
Memory: 104.0M
CPU: 3.978s
CGroup: /system.slice/docker.service
└─849 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock
Sep 15 22:40:05 suyi dockerd[849]: time="2024-09-15T22:40:05.285376658Z" level=info msg="Starting up"
Sep 15 22:40:05 suyi dockerd[849]: time="2024-09-15T22:40:05.291203704Z" level=info msg="detected 127.0.0.53 nameserver, assuming systemd-resolved, so using resolv.conf: /run/systemd/resolve/resolv.con>
Sep 15 22:40:05 suyi dockerd[849]: time="2024-09-15T22:40:05.940404598Z" level=info msg="[graphdriver] using prior storage driver: overlay2"
Sep 15 22:40:06 suyi dockerd[849]: time="2024-09-15T22:40:06.148735504Z" level=info msg="Loading containers: start."
Sep 15 22:40:07 suyi dockerd[849]: time="2024-09-15T22:40:07.612112932Z" level=info msg="Default bridge (docker0) is assigned with an IP address 172.17.0.0/16. Daemon option --bip can be used to set a >
Sep 15 22:40:07 suyi dockerd[849]: time="2024-09-15T22:40:07.809976695Z" level=info msg="Loading containers: done."
Sep 15 22:40:07 suyi dockerd[849]: time="2024-09-15T22:40:07.914247738Z" level=info msg="Docker daemon" commit=f9522e5 containerd-snapshotter=false storage-driver=overlay2 version=27.1.2
Sep 15 22:40:07 suyi dockerd[849]: time="2024-09-15T22:40:07.919455394Z" level=info msg="Daemon has completed initialization"
Sep 15 22:40:08 suyi dockerd[849]: time="2024-09-15T22:40:08.168499249Z" level=info msg="API listen on /run/docker.sock"
Sep 15 22:40:08 suyi systemd[1]: Started Docker Application Container Engine.
Modifying services
Start a service:
sudo systemctl start docker
Stop a service:
sudo systemctl stop docker
Set service to start at boot:
sudo systemctl enable docker
Disable a service from starting at boot:
sudo systemctl disable docker
Troubleshooting Failed Services
Inspect a service logs:
sudo journalctl -u docker
This tool helps identify problems by displaying logs unique to the service.
Show logs with pattern
sudo journalctl -u docker -g error
Aug 22 01:32:54 suyi dockerd[834]: 2024/08/22 01:32:54 http2: server: error reading preface from client @: read unix /run/docker.sock->@: read: connection reset by peer
Aug 22 01:32:54 suyi dockerd[834]: 2024/08/22 01:32:54 http2: server: error reading preface from client @: read unix /run/docker.sock->@: read: connection reset by peer
Aug 22 02:13:05 suyi dockerd[834]: 2024/08/22 02:13:05 http2: server: error reading preface from client @: read unix /run/docker.sock->@: read: connection reset by peer
Aug 22 02:16:26 suyi dockerd[834]: 2024/08/22 02:16:26 http2: server: error reading preface from client @: read unix /run/docker.sock->@: read: connection reset by peer
Aug 22 02:16:26 suyi dockerd[834]: 2024/08/22 02:16:26 http2: server: error reading preface from client @: read unix /run/docker.sock->@: read: connection reset by peer
Aug 22 02:23:22 suyi dockerd[834]: 2024/08/22 02:23:22 http2: server: error reading preface from client @: read unix /run/docker.sock->@: read: connection reset by peer
Aug 22 02:34:33 suyi dockerd[834]: 2024/08/22 02:34:33 http2: server: error reading preface from client @: read unix /run/docker.sock->@: read: connection reset by peer
Aug 22 02:36:47 suyi dockerd[834]: time="2024-08-22T02:36:47.096274670Z" level=error msg="Handler for POST /v1.46/containers/44aa166cbfa74151ecf91b9a8b1894c4a65d0357e819404a0187f4726ed2ea3b/start retur>
Aug 22 02:52:35 suyi dockerd[834]: 2024/08/22 02:52:35 http2: server: error reading preface from client @: read unix /run/docker.sock->@: read: connection reset by peer
Aug 22 02:52:35 suyi dockerd[834]: 2024/08/22 02:52:35 http2: server: error reading preface from client @: read unix /run/docker.sock->@: read: connection reset by peer
Aug 22 02:52:58 suyi dockerd[834]: time="2024-08-22T02:52:58.885877415Z" level=error msg="Handler for POST /v1.46/containers/33caaaef459e7815dc0b7b19fb6013c75da4f8c30461449133651fdc2cb24f9d/start retur>
Aug 22 02:53:33 suyi dockerd[834]: time="2024-08-22T02:53:33.614744234Z" level=error msg="Handler for GET /v1.46/nodes returned error: This node is not a swarm manager. Use \"docker swarm init\" or \"d>
Aug 22 02:53:33 suyi dockerd[834]: time="2024-08-22T02:53:33.725262538Z" level=error msg="Handler for GET /v1.46/secrets returned error: This node is not a swarm manager. Use \"docker swarm init\" or \>
Aug 22 02:53:33 suyi dockerd[834]: time="2024-08-22T02:53:33.779312716Z" level=error msg="Handler for GET /v1.46/services returned error: This node is not a swarm manager. Use \"docker swarm init\" or >
Aug 22 03:34:32 suyi dockerd[834]: 2024/08/22 03:34:32 http2: server: error reading preface from client @: read unix /run/docker.sock->@: read: connection reset by peer
Aug 22 04:00:07 suyi dockerd[834]: 2024/08/22 04:00:07 http2: server: error reading preface from client @: read unix /run/docker.sock->@: read: connection reset by peer
Aug 22 04:07:58 suyi dockerd[834]: time="2024-08-22T04:07:58.336371559Z" level=error msg="Handler for GET /v1.46/containers/3f5ae5a0e2d4d31ee2b2a1e7349dc8f3b974357ad07d38058977dde457d64b00/json returne>
Aug 22 23:36:58 suyi dockerd[834]: time="2024-08-22T23:36:58.345922273Z" level=info msg="stopping event stream following graceful shutdown" error="<nil>" module=libcontainerd namespace=moby
-- Boot 669604f4faaf48118f69cf972a727357 --
Aug 22 23:39:59 suyi dockerd[834]: time="2024-08-22T23:39:59.284875890Z" level=info msg="stopping event stream following graceful shutdown" error="<nil>" module=libcontainerd namespace=moby
-- Boot c6e44628725942cba7220cce9f50ee24 --
Aug 26 03:33:25 suyi dockerd[836]: time="2024-08-26T03:33:25.334907163Z" level=info msg="Attempting next endpoint for pull after error: failed to register layer: write /usr/share/opensearch/jdk/jmods/j>
Ref: https://webhostinggeeks.com/howto/how-to-list-manage-and-troubleshoot-services-in-ubuntu/
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