One liner with grep to extract the IP addresses from a file.

The "-o" option prints only the matched parts.

One liner with perl:

The journal is located at inode:

The size of journal in Bytes is:

Note: "<>" is necessary around the inode number.

Often times, there is need for web-accessible folders to be set up so all web-developers have write access.

Along with setgid option, ACL can be used so anyone in the group "web-developers"
would have write privileges to anything under web-accessible document root.

So unless the acl privileges is revoked specifically, it would just continue to work.

To enable ACL, add "acl" option to /etc/fstab file for the corresponding partition and remount.

Edit /etc/fstab:

Remount:

Here is the commands to be used for the setup:

Now anyone needing write access can be put in the "developers" group.

If you need the webserver to have write access to certain folders, then chown the location to be owned by the webserver, instead of giving write permissions to all.

The grub bootloader is particularly useful, especially when upgrading and testing new kernels. I recently found a way to modifiy the default boot config to make it useful when you wish to remotely upgrade a kernel and boot into it once only without being at the console to change the default back.

• munin-node installed via epel repository.
  
• Install perl-Cache-Cache:
  
  # yum install munin-node perl-Cache-Cache
• Create file "/etc/munin/plugin-conf.d/mysql" with below contents:
  
  [mysql*]
env.mysqluser munin
env.mysqlpassword {PASS}
• Create mysql user and assign corresponding privileges:
  
  mysql> create user munin@localhost identified by '{PASS}';
mysql> GRANT PROCESS, SUPER ON *.* TO 'munin'@'localhost';
mysql> GRANT SELECT ON `mysql`.* TO 'munin'@'localhost';
mysql> flush privileges
• Check the suggestions and install the plugins:
  
  munin-node-configure  --suggest 2>/dev/null |grep mysql
munin-node-configure  --shell | grep mysql | sh
• Test via:
  
  # cd /etc/munin/plugins
# munin-run mysql_connections

Java is a programming language and computing platform first released by Sun Microsystems in 1995. It is the underlying technology that powers state-of-the-art programs including utilities, games, and business applications. Java runs on more than 850 million personal computers worldwide, and on billions of devices worldwide, including mobile and TV devices.

After Plesk upgrade to 9.5.4, imapd on port 143 did not come up.

On checking the maillog, it was complaining about:

I noticed /etc/courier-imap/imapd had both the below lines commented:

Once I uncommented those values, I was able to get the imap listener up upon a `service courier-imap restart`.

Recently, I've had to move a postgresql database onto a separate server and split it out from the django application server.

On doing so, we saw intermittent "OperationalError: could not connect to server: Connection timed out".

This was quite obvious that the "connect_timeout" had to be increased to resolve the issue due to the latency introduced by the network. However, psycopg2 database adapter was being used which did not support the "connect_timeout" option to be passed via django.

We were able to work around the issue setting the environmental variable "PGCONNECT_TIMEOUT" so libpq would pick up the connection parameter.

Put the below in "django.wsgi":

While setting up munin to monitor postgresql, I was getting "[DBD::Pg not found, and cannot do psql yet]" when running `munin-node-configure --suggest | grep postgres`.

I confirmed that the rpm package "perl-DBI-1.52-2.el5" was indeed installed.

However, when I ran a test against the module, it failed with:

On checking the library, it returned with "libpq.so.4 => not found":

Indeed libpq.so.4 was missing since postgresql90-libs was installed which only includes "libpq.so.5".

To get libpq.so.4, "compat-postgresql-libs" package needed to be installed.

Once installed the perl module test passed and I was able to get the munin plugins linked using:

RNDC is a useful mechanism for administering DNS servers. If it is not configured, BIND complains about it.

Determine the locations where RNDC expects to find the config files.

Create the rndc config file:

Thy rndc conf file should also have the contents that need to go to "/etc/named.conf". See sample below:

Once the key and control section has been added to named.conf, restart named and test again with: