System V style init and systemd in practice

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Administration with systemadm (systemd)

This GUI program, available on Ubuntu via the systemd-ui package, makes it possible to quickly and easily administer systemd and the services [5][6].

The interface is self-explanatory and the operation itself takes little getting used to. Figure 10 shows a status request.

Figure 10: Status notification with systemadm.

syslog vs. journald

Now that you are using systemd for your services, you should also use systemd-journald instead of syslog . This can be handled as you prefer. For example, you can change from syslog to systemd-journald or vice versa.

When you use journald , the log data will only be saved during runtime. You can modify the configuration by changing entries in /etc/systemd/journald.conf . By using the setting Storage=persistent you can permanently save the journal in /var/log/journal . You should limit the size of the log with something like SystemMaxUse=100M . Listing 8 shows all of the items in this file that have been modified. Note that the log files from systemd/journald are not searchable with customary text tools like find, grep, etc. You will need to use journalctl .

Listing 8

Storing Logs Using journald

01 [Journal]
02 Storage=persistent
03 ......
04 SystemMaxUse=100M
05 ......

To see the logs using journalctl , you can enter the command without any other option and the program will list a complete journal. Table 8 contains some filtering possibilities.

Table 8

Journalctl – Important Options

Limit to one unit -u UNIT
Kernel messages -k
Additional output of plaintext explanations -x
Running display -f

Figure 11 shows a journal request that was limited to one service, apache.2service .

Figure 11: Journal inquiry for apache2.service.

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