How To Configuration file is not writable in linux centos 7

You may require SELinux to be enabled. But if you try to test or configure new applications in your CentOS 7 operating system while SELinux is enabled, even the right configuration may not work. For example, if you have Apache web server installed, the default web root is /var/www/html. If you have SELinux enabled, and you try to change it to something else, Apache web server won’t start unless you reconfigure SELinux. In situations like this, you may want to disable SELinux temporarily. But SELinux can’t be disabled without a system reboot. You may consider changing SELinux mode to permissive. That way SELinux policy won’t be enforced, which is kind of the same as disabling SELinux. When you’re done, you can set SELinux to enforcing mode again. You can run the following command to set SELinux to permissive mode temporarily:

$ sudo setenforce 0

Now run the following command to check the current mode of SELinux:

$ sudo sestatus

As you can see in the marked section of the screenshot below, SELinux is set to permissive mode.

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