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Exhaustive checking system: internal server checkers

Core-Admin includes a complete and a growing list of checkers to test many aspects of your servers and systems. This ensures that they are working, so giving you an accurate view about the current state of the entire system

Core-Admin’s checkers

Core-Admin’s internal checking design is based on real time log analysis done through Core-Admin Log watcher and a list of especialized checkers that are run by the Core-Admin agent to ensure that your server is properly working. They provide the basis for the exhaustive checking system that provides Core-Admin.

Lost of ready to use checkers

checker-64x64 Core-Admin already includes lot of ready to use checkers that are able self-detect the system to see if they can run. In that case, they start to work, checking regularly your system, producing useful notifications when something wrong is found.

Extensible system!

tools Did you find some checker missing? Core-Admin will help you to create easily new checkers to suit your needs. You will be able to add custom-made options to your checkers to implement nearly any operation you need.

Not just notifications

event-64x64 Many checkers produce not only a notification when something is going wrong. Along those notifications the checker provides many options that can be used to fix the problem, reconfigure the checker or to suspend it temporaly (to name some).

Official list of checkers bundled with Core-Admin

The following is the list of currently supported checkers, that is, checkers that are maintained by ASPL and bundled in all core-admin editions:

Checker	Description	What it solves
apache2	Checks current apache2 function by connecting to the local ports detected. In the case something is not working, it can restart the server.	Detecting when apache2 is not working and restarting it when it is found to be failing.
arcconf	Checks Adaptec and PMC-sierra hardware raid cards that support arcconf tool.	Allows to detect raid failures so operators can proceed to replace disks. Because detection is done early, it reduces the chances to be working with a faulting device.
cpu-usage	Checks for high cpu consumption patterns by individual or group of processes.	Detecting excesive cpu consumption patterns which are usually a sign of something not working properly or a service misuse.
disk-full	Checks and watches hard disks do not fill.	Early detection when a server is running out of space.
dns	Checks current configured DNS servers are working and resolving names.	Many server components depends on having DNS working properly. Without it, the server produces many additional errors that are in fact consequence of the first error.
fstab	Checks that all declarations found in /etc/fstab make sense. It ensures all devices and file systems declared are supported.	Avoid having a broken /etc/fstab which may render the server unusable especially after reboot.
generic-ftp	Checks that local FTP server is working. It supports providing user and password for extended checking.	Ensures current FTP server is working.
generic-mail	Checks that local IMAP and POP3 server is working. It supports providing user and password for extended checking.	Ensures current IMAP and POP3 server is working. It allows server restart when it is found not working.
generic-smtp	Checks that local SMTP server is working. It supports providing user and password for extended checking.	Ensures current SMTP server is working. It allows server restart when it is found not working.
hostname	Checks that current hostname, host ip and internal declarations matches and are right	Many applications may provide herratic or wrong behavior with wrongly configured hostname
hpacucli	Checks HP Smart Array hardware raid cards that support hpacucli tool.	Allows to detect raid failures so operators can proceed to replace disks. Because detection is done early, it reduces the chances to be working with a faulting device.
iptables-running	Ensures iptables based firewall is running	Allows to detect when the firewall is down when it shouldn’t. It also support taking it up automatically.
ldap	Checks that local LDAP server is working.	Allows to ensure LDAP server is working and reporting valid results.
loopback-check	Ensures loopback device is present and working	Many applications show herratic or wrong behavior when loopback device is not present or it is not properly configured.
mdadm	Checks Linux Software RAID based on mdadm tool	Allows to detect raid failures so operators can proceed to replace disks. Because detection is done early, it reduces the chances to be working with a faulting device.
megaraid	Checks MegaRaid hardware raid cards that support megaraidsas-status or megaraid-status tool.	Allows to detect raid failures so operators can proceed to replace disks. Because detection is done early, it reduces the chances to be working with a faulting device.
mysql	Checks local MySQL server is working, it replies queries and it has connections available	Allows to ensure MySQL server is working and has always enough connections available to make server systems that depend on it to work properly.
ntp	Checks and fixes server time by checking a remote time server.	To ensure the server has always the clock sync.
rbl-check	Checks if any of the server’s IP got listed at known DNS blacklists	To help improve server IP reputation by spoting quickly when the server got listed, providing information about the list, the server and IP that are involved.
renamed-process	Implements various checks to find suspicious processes with unexpected loading paths or changing names attempting to hide themselves.	To help improve security by detecting common suspicious patterns.
time_wait	Implements various checks to ensure there are ephemeral ports available.	To ensure and help to solve ephemeral port exhaustion problems.
samba	Checks samba server is working and it servers requests	To ensure samba server is working. Checker supports restarting the server if it find it not working.
swap-working	Implements various checks around swap declarations to ensure they are available and that its usage do not go beyond a certain threshold.	To ensure the system works under reasonable memory values. High swap usage usually indicates something is not working properly and there is a usage pattern that may give problems.
syncookie	Checks and ensure syncookie protection is enabled	To ensure this basic syn-flood protection is enabled.
syn-flood-detect	Checks syn-flood attacks and automatically block them.	To improve protection against syn-flood attacks.
tmp-working	Implements various checks to ensure system /tmp is working	To ensure temporal directory is working and it is available. Many system components depends on having /tmp working.
unknown-dhcp-servers	Allows to detect unknown/unexpected DHCP servers	To ensure DHCP servers are known and no other server provides DHCP replies
uptime	Allows to track uptime to detect reboots	To detect various suspicous patterns around uptime value.
varnish	Checks varnishd cache server status and its default backend	To detect wrong varnish status, reporiting failures and optionally, restarting the service.