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daemon administratie: systemctl

Sedert 2016 gebruiken redhat, debian, ubuntu en linux mint het pakket systemd voor service beheer
Een uitgebreide uitleg vind je hier: digital ocean systemd.
 
We tonen kort de belangrijkste funkties:
 

  1. status van openssh tonen: [systemctl status naam.service]
     
    user@mint18-srv ~ $ sudo systemctl status ssh.service
    ● ssh.service - OpenBSD Secure Shell server
    Loaded: loaded (/lib/systemd/system/ssh.service; enabled; vendor preset: enab
    Active: active (running) since Wed 2017-05-31 15:19:38 CEST; 1h 8min ago
    Main PID: 2620 (sshd)
    CGroup: /system.slice/ssh.service
           └─2620 /usr/sbin/sshd -D
     
    May 31 15:19:38 mint18-srv systemd[1]: Starting OpenBSD Secure Shell server...
    May 31 15:19:38 mint18-srv sshd[2620]: Server listening on 0.0.0.0 port 22.
    May 31 15:19:38 mint18-srv sshd[2620]: Server listening on :: port 22.
    May 31 15:19:38 mint18-srv systemd[1]: Started OpenBSD Secure Shell server.
    May 31 15:55:57 mint18-srv sshd[2924]: Accepted password for bert from 127.0.0.1
    May 31 15:55:57 mint18-srv sshd[2924]: pam_unix(sshd:session): session opened ..

     

  2. ssh-daemon stoppen: [systemctl stop naam.service]
     
    user@mint18-srv ~ $ sudo systemctl stop ssh.service
    (de command line zegt niets we moeten de status opvragen ...)
    user@mint18-srv ~ $ systemctl status ssh.service
    ● ssh.service - OpenBSD Secure Shell server
    Loaded: loaded (/lib/systemd/system/ssh.service; enabled; vendor preset: enab
    Active: inactive (dead) since Wed 2017-05-31 16:31:10 CEST; 4s ago
    Main PID: 2620 (code=exited, status=0/SUCCESS)
    ...
    May 31 16:31:10 mint18-srv systemd[1]: Stopping OpenBSD Secure Shell server...
    May 31 16:31:10 mint18-srv systemd[1]: Stopped OpenBSD Secure Shell server.

     

  3. ssh-daemon starten: [systemctl start naam.service]
     
    user@mint18-srv ~ $ sudo systemctl start ssh.service
    user@mint18-srv ~ $ systemctl status ssh.service
    ● ssh.service - OpenBSD Secure Shell server
    Loaded: loaded (/lib/systemd/system/ssh.service; enabled; vendor preset: enabled)
    Active: active (running) since Wed 2017-05-31 16:36:19 CEST; 5s ago
    Main PID: 3046 (sshd)
    CGroup: /system.slice/ssh.service
           └─3046 /usr/sbin/sshd -D
    May 31 16:36:19 mint18-srv systemd[1]: Starting OpenBSD Secure Shell server...
    May 31 16:36:19 mint18-srv sshd[3046]: Server listening on 0.0.0.0 port 22.
    May 31 16:36:19 mint18-srv sshd[3046]: Server listening on :: port 22.
    May 31 16:36:19 mint18-srv systemd[1]: Started OpenBSD Secure Shell server.

     

  4. ssh-daemon herstarten: [systemctl restart naam.service]
     
    herstarten is een stop gevolgd door een start
     
    user@mint18-srv ~ $ sudo systemctl restart ssh.service
    user@mint18-srv ~ $ systemctl status ssh.service
    ● ssh.service - OpenBSD Secure Shell server
    Loaded: loaded (/lib/systemd/system/ssh.service; enabled; vendor preset: enabled)
    Active: active (running) since Wed 2017-05-31 16:40:56 CEST; 1s ago
    Main PID: 3055 (sshd)
    CGroup: /system.slice/ssh.service
           └─3055 /usr/sbin/sshd -D
    May 31 16:40:56 mint18-srv systemd[1]: Starting OpenBSD Secure Shell server...
    May 31 16:40:56 mint18-srv sshd[3055]: Server listening on 0.0.0.0 port 22.
    May 31 16:40:56 mint18-srv sshd[3055]: Server listening on :: port 22.
    May 31 16:40:56 mint18-srv systemd[1]: Started OpenBSD Secure Shell server.

    Merk op dat de PID veranderd is van 3046 naar 3055
     

  5. ssh-daemon reloaden: [systemctl reload naam.service]
     
    reloaden is een herinladen van de config-file (meestal na aanpassingen)
     
    user@mint18-srv ~ $ sudo systemctl reload ssh.service
    user@mint18-srv ~ $ systemctl status ssh.service
    ● ssh.service - OpenBSD Secure Shell server
    Loaded: loaded (/lib/systemd/system/ssh.service; enabled; vendor preset: enabled)
    Active: active (running) since Wed 2017-05-31 16:40:56 CEST; 4min 21s ago
    Process: 3064 ExecReload=/bin/kill -HUP $MAINPID (code=exited, status=0/SUCCESS)
    Main PID: 3055 (sshd)
    CGroup: /system.slice/ssh.service
           └─3055 /usr/sbin/sshd -D
    May 31 16:40:56 mint18-srv systemd[1]: Starting OpenBSD Secure Shell server...
    May 31 16:40:56 mint18-srv sshd[3055]: Server listening on 0.0.0.0 port 22.
    May 31 16:40:56 mint18-srv sshd[3055]: Server listening on :: port 22.
    May 31 16:40:56 mint18-srv systemd[1]: Started OpenBSD Secure Shell server.
    May 31 16:45:16 mint18-srv systemd[1]: Reloading OpenBSD Secure Shell server.
    May 31 16:45:16 mint18-srv sshd[3055]: Received SIGHUP; restarting.
    May 31 16:45:16 mint18-srv systemd[1]: Reloaded OpenBSD Secure Shell server.
    May 31 16:45:16 mint18-srv sshd[3055]: Server listening on 0.0.0.0 port 22.

    De PID is nu gelijk gebleven ...
     

  6. ssh-daemon dis-ablen: [systemctl disable naam.service]
     
    disable, betekent dat de service niet meer automatisch wordt opgestart bij booten van je server
     
    user@mint18-srv ~ $ sudo systemctl disable ssh.service
    Synchronizing state of ssh.service with SysV init with /lib/systemd/systemd-sysv-install...
    Executing /lib/systemd/systemd-sysv-install disable ssh
    insserv: warning: current start runlevel(s) (empty) of script `ssh' overrides LSB defaults (2 3 4 5).
    insserv: warning: current stop runlevel(s) (2 3 4 5) of script `ssh' overrides LSB defaults (empty).
    Removed symlink /etc/systemd/system/sshd.service.

    user@mint18-srv ~ $ systemctl status ssh.service

    ● ssh.service - OpenBSD Secure Shell server
    Loaded: loaded (/lib/systemd/system/ssh.service; disabled; vendor preset: enabled)
    Active: active (running) since di 2017-06-06 12:32:52 CEST; 6h ago

    Hoewel bij de volgende system restart de service niet meer automatisch zal opstarten, wordt die nu met rust gelaten, en blijft de ssh.service draaien.
     
    We herstarten de machine:
    user@mint18-srv ~ ~$ sudo init 6
    Connection to 192.168.5.240 closed by remote host. Connection to 192.168.5.240 closed.
     
    ... en proberen nadien terug in te loggen:
    frank@system3 ~ $ ssh user@192.168.5.240
    ssh: connect to host 192.168.5.240 port 22: Connection refused
     

  7. ssh-daemon en-ablen: [systemctl enable naam.service]
     
    enable, betekent dat de service automatisch zal worden opgestart bij elke boot van je server.
    bij het installeren van een service met apt wordt een service normaal gezien automatisch ge-enabled.
     
    user@mint18-srv ~ $ sudo systemctl enable ssh.service
    Synchronizing state of ssh.service with SysV init with /lib/systemd/systemd-sysv-install...
    Executing /lib/systemd/systemd-sysv-install enable ssh
    insserv: warning: current start runlevel(s) (empty) of script `ssh' overrides LSB defaults (2 3 4 5).
    insserv: warning: current stop runlevel(s) (2 3 4 5) of script `ssh' overrides LSB defaults (empty).
    Created symlink from /etc/systemd/system/sshd.service to /lib/systemd/system/ssh.service.

     

  8. oefening: probeer de voorbeelden van hierboven met systemctl op je eigen systeem