checkServer: A Shell repository from aleen42

checkServer

checkServer is a repository of a shell script snippet, which is mainly used for checking whether CPU or MEMORY of a server is normal. To enhance notification, the checked status will also be sent by emails.

1. Mutt

For mailing people, Mutt is the client what I chose for sending emails under Linux with POP3 protocol. the following tutorial has shown us how to install it under Ubuntu. For more detailed around installation on other Linux, like CentOS, please check the official site, or a third-party document searched before.

1.1 Installation via `apt-get`

The system name can be set with whatever name you like.

apt-get install mutt

1.2 Setup Configuration

Touch a file named .muttrc in the ~ directory of root user and edit it with following snippet:

# .mutttrc file
# sudo vi ~/.muttrc or /root/.muttrc
set envelope_from=yes
# the name of who sent the mail
set from=xxx@xx.cn
# the real name of who send the mail
set realname="VoiceIn Website"
set use_from=yes
set rfc2047_parameters=yes
set charset="utf-8"

1.3 Send Emails via Terminals

echo "Email Contents" | `which mutt` -s "Title" aleen42@vip.qq.com

2. Crontab

Crontab helps us to set up a series of tasks, which can be run at a fixed time in Linux.

The following case set here means that checkServer.sh will be executed on 9 pm every day.

0 21 * * * sh ./checkServer.sh false

3. Scripts Information

There is also some helpful information for you to understand shell scripts.

3.1 Parameters

MAX_mem(%): the upper edge of physical memory warning.
MAX_cpu(%): the upper edge of physical cpu warning.
DELAY(s): update every $delay seconds.
COUNT: update $count times.
NORMAL_CHECK: to identify whether it is just a normal check each day.
sh_command: point out where sh command is.
top_command: point out where top command is.
sar_command: point out [where sar command is.
iostat_command: point out where iostat command is.
free_command: point out where free command is.

3.2 Methods

checkServer: generate system information and send emails to the specified email address.

3.3 Extracting Number

To extracting number from terminals, I have used sed (The following case has got the row 3 and column 3 of results run by top command):

free | sed -n "3, 1p" | awk '{print int($3)}'

3.4 Attention

sar command need us to set ENABLED with true in the configuration file /etc/default/sysstat.

#
# Default settings for /etc/init.d/sysstat, /etc/cron.d/sysstat
# and /etc/cron.daily/sysstat files
#

# Should sadc collect system activity informations? Valid values
# are "true" and "false". Please do not put other values, they
# will be overwritten by debconf!
ENABLED="true"

# Additional options passed to sa1 by /etc/init.d/sysstat
# and /etc/cron.d/sysstat
# By default contains the `-S DISK' option responsible for
# generating disk statisitcs.
SA1_OPTIONS="-S DISK"

# Additional options passed to sa2 by /etc/cron.daily/sysstat.
SA2_OPTIONS=""

Otherwise, we may get the following error when running sar command:

root@xxx:/home/checkServer# sar
Cannot open /var/log/sysstat/sa16: No such file or directory
Please check if data collecting is enabled in /etc/default/sysstat

4. How to install it on your server?

clone it:

git clone https://github.com/aleen42/checkServer.git

install mutt service as mentioned above and check whether the following commands works:
```
mutt
```
```
sar
```

run it manually:

# options:
#	- true: normal check
#	- false: warning check
# email_addr: the email you want to receive infos of the server
sh ./checkServer.sh true aleen42@vip.qq.com

⛽ How to contribute

Have an idea? Found a bug? See how to contribute.

aleen42/checkServer