{"id":4564,"date":"2015-04-22T10:24:13","date_gmt":"2015-04-22T02:24:13","guid":{"rendered":"http:\/\/rmohan.com\/?p=4564"},"modified":"2015-04-22T10:24:13","modified_gmt":"2015-04-22T02:24:13","slug":"centos-remove-old-kernels","status":"publish","type":"post","link":"https:\/\/mohan.sg\/?p=4564","title":{"rendered":"CentOS Remove Old Kernels"},"content":{"rendered":"<p>Tonight when upgrading a CentOS Linux server it was noted by YUM that 15MB more disk space was needed to upgrade grub and the kernel itself. Below are four quick steps to verify what kernels are installed, install yum-utils if it is not installed already, delete previous kernels and set YUM to remove old kernels when new kernels are installed. Depending on the size of your \/boot directory you should make a decision on how many previous kernels you want to keep installed though I would recommend always keeping at least one previous kernel at a minimum. In the steps below we go off that recommendation and set YUM to always keep two kernels which would include the current kernel and one previous kernel.<\/p>\n<h2>YUM Warning Regarding \/boot Disk Space:<\/h2>\n<p>As you can see below during the transaction test YUM runs during package installation, upgrades, etc. there is a warning that stops the update process because there is not enough room on the \/boot partition.<\/p>\n<div>\n<div id=\"highlighter_927370\" class=\"syntaxhighlighter nogutter  bash\">\n<table border=\"0\" cellspacing=\"0\" cellpadding=\"0\">\n<tbody>\n<tr>\n<td class=\"code\">\n<div class=\"container\">\n<div class=\"line number1 index0 alt2\"><code class=\"bash plain\">Total\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 8.5 MB<\/code><code class=\"bash plain\">\/s<\/code> <code class=\"bash plain\">| 167 MB\u00a0\u00a0\u00a0\u00a0 00:19<\/code><\/div>\n<div class=\"line number2 index1 alt1\"><code class=\"bash plain\">Running rpm_check_debug<\/code><\/div>\n<div class=\"line number3 index2 alt2\"><code class=\"bash plain\">Running Transaction Test<\/code><\/div>\n<div class=\"line number4 index3 alt1\"><\/div>\n<div class=\"line number5 index4 alt2\"><code class=\"bash plain\">Transaction Check Error:<\/code><\/div>\n<div class=\"line number6 index5 alt1\"><code class=\"bash spaces\">\u00a0\u00a0<\/code><code class=\"bash plain\">installing package kernel-2.6.32-431.17.1.el6.centos.plus.x86_64 needs 15MB on the <\/code><code class=\"bash plain\">\/boot<\/code> <code class=\"bash plain\">filesystem<\/code><\/div>\n<div class=\"line number7 index6 alt2\"><code class=\"bash spaces\">\u00a0\u00a0<\/code><code class=\"bash plain\">installing package grub-1:0.97-83.el6.x86_64 needs 15MB on the <\/code><code class=\"bash plain\">\/boot<\/code> <code class=\"bash plain\">filesystem<\/code><\/div>\n<div class=\"line number8 index7 alt1\"><\/div>\n<div class=\"line number9 index8 alt2\"><code class=\"bash plain\">Error Summary<\/code><\/div>\n<div class=\"line number10 index9 alt1\"><code class=\"bash plain\">-------------<\/code><\/div>\n<div class=\"line number11 index10 alt2\"><code class=\"bash plain\">Disk Requirements:<\/code><\/div>\n<div class=\"line number12 index11 alt1\"><code class=\"bash spaces\">\u00a0\u00a0<\/code><code class=\"bash plain\">At least 15MB <\/code><code class=\"bash functions\">more<\/code> <code class=\"bash plain\">space needed on the <\/code><code class=\"bash plain\">\/boot<\/code> <code class=\"bash plain\">filesystem.<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<p>Once you receive that warning it is always good to manually check the disk space left on the server to verify YUM is reporting accurately. You can see in the below output from a CentOS Linux server that there is only 14MB of disk space available and YUM is reporting that it needs at least 29MB of disk space to complete the grub and kernel upgrades.<\/p>\n<h2>Show Disk Usage Per Partition on CentOS Linux:<\/h2>\n<div>\n<div id=\"highlighter_448464\" class=\"syntaxhighlighter nogutter  bash\">\n<table border=\"0\" cellspacing=\"0\" cellpadding=\"0\">\n<tbody>\n<tr>\n<td class=\"code\">\n<div class=\"container\">\n<div class=\"line number1 index0 alt2\"><code class=\"bash plain\">[root@dev ~<\/code><code class=\"bash comments\"># df -kh<\/code><\/div>\n<div class=\"line number2 index1 alt1\"><code class=\"bash plain\">Filesystem Size Used Avail Use% Mounted on<\/code><\/div>\n<div class=\"line number3 index2 alt2\"><code class=\"bash plain\">\/dev\/sda3<\/code> <code class=\"bash plain\">228G 22G 194G 11% \/<\/code><\/div>\n<div class=\"line number4 index3 alt1\"><code class=\"bash plain\">tmpfs 1.9G 0 1.9G 0% <\/code><code class=\"bash plain\">\/dev\/shm<\/code><\/div>\n<div class=\"line number5 index4 alt2\"><code class=\"bash plain\">\/dev\/sda1<\/code> <code class=\"bash plain\">99M 81M 14M 87% <\/code><code class=\"bash plain\">\/boot<\/code><\/div>\n<div class=\"line number6 index5 alt1\"><code class=\"bash plain\">[root@dev ~]<\/code><code class=\"bash comments\">#<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<p>Follow the steps below to list currently installed kernels on your CentOS server, install yum-utils for the package-cleanup command, remove the oldest kernels on the CentOS Linux server and configure YUM to automatically remove older kernels when new kernels are installed in the future.<\/p>\n<h1><strong>Remove Previous CentOS Linux Kernels:<\/strong><\/h1>\n<ol>\n<li><strong>List Installed\u00a0CentOS Linux Kernels:<\/strong><span class=\"Apple-converted-space\">\u00a0<\/span>Use the RPM command listed in the example below to list the set of kernels currently installed on your CentOS Linux server.\n<div>\n<div id=\"highlighter_913403\" class=\"syntaxhighlighter nogutter  bash\">\n<table border=\"0\" cellspacing=\"0\" cellpadding=\"0\">\n<tbody>\n<tr>\n<td class=\"code\">\n<div class=\"container\">\n<div class=\"line number1 index0 alt2\"><code class=\"bash plain\">[root@dev ~]<\/code><code class=\"bash comments\"># rpm -q kernel<\/code><\/div>\n<div class=\"line number2 index1 alt1\"><code class=\"bash plain\">kernel-2.6.32-358.el6.x86_64<\/code><\/div>\n<div class=\"line number3 index2 alt2\"><code class=\"bash plain\">kernel-2.6.32-358.6.2.el6.x86_64<\/code><\/div>\n<div class=\"line number4 index3 alt1\"><code class=\"bash plain\">kernel-2.6.32-358.18.1.el6.x86_64<\/code><\/div>\n<div class=\"line number5 index4 alt2\"><code class=\"bash plain\">[root@dev ~]<\/code><code class=\"bash comments\">#<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/li>\n<li><strong>Install YUM Utilities Package On CentOS Linux:<\/strong><span class=\"Apple-converted-space\">\u00a0<\/span>Now install the yum-utils package on Linux as shown in the example command below.\n<div>\n<div id=\"highlighter_565141\" class=\"syntaxhighlighter nogutter  bash\">\n<table border=\"0\" cellspacing=\"0\" cellpadding=\"0\">\n<tbody>\n<tr>\n<td class=\"code\">\n<div class=\"container\">\n<div class=\"line number1 index0 alt2\"><code class=\"bash plain\">[root@dev ~]<\/code><code class=\"bash comments\"># yum install yum-utils<\/code><\/div>\n<div class=\"line number2 index1 alt1\"><code class=\"bash plain\">Loaded plugins: fastestmirror, security<\/code><\/div>\n<div class=\"line number3 index2 alt2\"><code class=\"bash plain\">Loading mirror speeds from cached hostfile<\/code><\/div>\n<div class=\"line number4 index3 alt1\"><code class=\"bash spaces\">\u00a0<\/code><code class=\"bash plain\">* atomic: www8.atomicorp.com<\/code><\/div>\n<div class=\"line number5 index4 alt2\"><code class=\"bash spaces\">\u00a0<\/code><code class=\"bash plain\">* epel: mirror.compevo.com<\/code><\/div>\n<div class=\"line number6 index5 alt1\"><code class=\"bash spaces\">\u00a0<\/code><code class=\"bash plain\">* rpmforge: mirror.team-cymru.org<\/code><\/div>\n<div class=\"line number7 index6 alt2\"><code class=\"bash plain\">Setting up Install Process<\/code><\/div>\n<div class=\"line number8 index7 alt1\"><code class=\"bash plain\">Resolving Dependencies<\/code><\/div>\n<div class=\"line number9 index8 alt2\"><code class=\"bash plain\">--&gt; Running transaction check<\/code><\/div>\n<div class=\"line number10 index9 alt1\"><code class=\"bash plain\">---&gt; Package yum-utils.noarch 0:1.1.30-14.el6 will be updated<\/code><\/div>\n<div class=\"line number11 index10 alt2\"><code class=\"bash plain\">---&gt; Package yum-utils.noarch 0:1.1.30-17.el6_5 will be an update<\/code><\/div>\n<div class=\"line number12 index11 alt1\"><code class=\"bash plain\">--&gt; Finished Dependency Resolution<\/code><\/div>\n<div class=\"line number13 index12 alt2\"><\/div>\n<div class=\"line number14 index13 alt1\"><code class=\"bash plain\">Dependencies Resolved<\/code><\/div>\n<div class=\"line number15 index14 alt2\"><code class=\"bash plain\">===============================================================================================================================<\/code><\/div>\n<div class=\"line number16 index15 alt1\"><code class=\"bash spaces\">\u00a0<\/code><code class=\"bash plain\">Package\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Arch\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Version\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Repository\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Size<\/code><\/div>\n<div class=\"line number17 index16 alt2\"><code class=\"bash plain\">===============================================================================================================================<\/code><\/div>\n<div class=\"line number18 index17 alt1\"><code class=\"bash plain\">Updating:<\/code><\/div>\n<div class=\"line number19 index18 alt2\"><code class=\"bash spaces\">\u00a0<\/code><code class=\"bash plain\">yum-utils\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 noarch\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 1.1.30-17.el6_5\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 updates\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 102 k<\/code><\/div>\n<div class=\"line number20 index19 alt1\"><code class=\"bash plain\">Transaction Summary<\/code><\/div>\n<div class=\"line number21 index20 alt2\"><code class=\"bash plain\">===============================================================================================================================<\/code><\/div>\n<div class=\"line number22 index21 alt1\"><code class=\"bash plain\">Upgrade\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 1 Package(s)<\/code><\/div>\n<div class=\"line number23 index22 alt2\"><\/div>\n<div class=\"line number24 index23 alt1\"><code class=\"bash plain\">Total size: 102 k<\/code><\/div>\n<div class=\"line number25 index24 alt2\"><code class=\"bash plain\">Is this ok [y<\/code><code class=\"bash plain\">\/N<\/code><code class=\"bash plain\">]: y<\/code><\/div>\n<div class=\"line number26 index25 alt1\"><code class=\"bash plain\">Downloading Packages:<\/code><\/div>\n<div class=\"line number27 index26 alt2\"><code class=\"bash plain\">Running rpm_check_debug<\/code><\/div>\n<div class=\"line number28 index27 alt1\"><code class=\"bash plain\">Running Transaction Test<\/code><\/div>\n<div class=\"line number29 index28 alt2\"><code class=\"bash plain\">Transaction Test Succeeded<\/code><\/div>\n<div class=\"line number30 index29 alt1\"><code class=\"bash plain\">Running Transaction<\/code><\/div>\n<div class=\"line number31 index30 alt2\"><code class=\"bash spaces\">\u00a0\u00a0<\/code><code class=\"bash plain\">Updating\u00a0\u00a0 : yum-utils-1.1.30-17.el6_5.noarch\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 1<\/code><code class=\"bash plain\">\/2<\/code><\/div>\n<div class=\"line number32 index31 alt1\"><code class=\"bash spaces\">\u00a0\u00a0<\/code><code class=\"bash plain\">Cleanup\u00a0\u00a0\u00a0 : yum-utils-1.1.30-14.el6.noarch\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 2<\/code><code class=\"bash plain\">\/2<\/code><\/div>\n<div class=\"line number33 index32 alt2\"><code class=\"bash spaces\">\u00a0\u00a0<\/code><code class=\"bash plain\">Verifying\u00a0 : yum-utils-1.1.30-17.el6_5.noarch\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 1<\/code><code class=\"bash plain\">\/2<\/code><\/div>\n<div class=\"line number34 index33 alt1\"><code class=\"bash spaces\">\u00a0\u00a0<\/code><code class=\"bash plain\">Verifying\u00a0 : yum-utils-1.1.30-14.el6.noarch\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 2<\/code><code class=\"bash plain\">\/2<\/code><\/div>\n<div class=\"line number35 index34 alt2\"><code class=\"bash plain\">Updated:<\/code><\/div>\n<div class=\"line number36 index35 alt1\"><code class=\"bash spaces\">\u00a0\u00a0<\/code><code class=\"bash plain\">yum-utils.noarch 0:1.1.30-17.el6_5\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Complete!<\/code><\/div>\n<div class=\"line number37 index36 alt2\"><code class=\"bash plain\">[root@dev ~]<\/code><code class=\"bash comments\">#<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/li>\n<li><strong>Remove Older CentOS Linux Kernels:<\/strong><span class=\"Apple-converted-space\">\u00a0<\/span>Once the CentOS yum-utils package has been installed you will now have access to the package-cleanup command which will allow us to easily remove previous CentOS Linux kernels as shown in the below example command output.\n<div>\n<div id=\"highlighter_721345\" class=\"syntaxhighlighter nogutter  bash\">\n<table border=\"0\" cellspacing=\"0\" cellpadding=\"0\">\n<tbody>\n<tr>\n<td class=\"code\">\n<div class=\"container\">\n<div class=\"line number1 index0 alt2\"><code class=\"bash plain\">[root@dev ~]<\/code><code class=\"bash comments\"># package-cleanup --oldkernels --count=2<\/code><\/div>\n<div class=\"line number2 index1 alt1\"><code class=\"bash plain\">Loaded plugins: fastestmirror<\/code><\/div>\n<div class=\"line number3 index2 alt2\"><code class=\"bash plain\">Loading mirror speeds from cached hostfile<\/code><\/div>\n<div class=\"line number4 index3 alt1\"><code class=\"bash spaces\">\u00a0<\/code><code class=\"bash plain\">* atomic: www8.atomicorp.com<\/code><\/div>\n<div class=\"line number5 index4 alt2\"><code class=\"bash spaces\">\u00a0<\/code><code class=\"bash plain\">* epel: mirror.steadfast.net<\/code><\/div>\n<div class=\"line number6 index5 alt1\"><code class=\"bash spaces\">\u00a0<\/code><code class=\"bash plain\">* rpmforge: mirror.team-cymru.org<\/code><\/div>\n<div class=\"line number7 index6 alt2\"><code class=\"bash plain\">--&gt; Running transaction check<\/code><\/div>\n<div class=\"line number8 index7 alt1\"><code class=\"bash plain\">---&gt; Package kernel.x86_64 0:2.6.32-358.el6 will be erased<\/code><\/div>\n<div class=\"line number9 index8 alt2\"><code class=\"bash plain\">--&gt; Finished Dependency Resolution<\/code><\/div>\n<div class=\"line number10 index9 alt1\"><\/div>\n<div class=\"line number11 index10 alt2\"><code class=\"bash plain\">Dependencies Resolved<\/code><\/div>\n<div class=\"line number12 index11 alt1\"><code class=\"bash plain\">===============================================================================================================================<\/code><\/div>\n<div class=\"line number13 index12 alt2\"><code class=\"bash spaces\">\u00a0<\/code><code class=\"bash plain\">Package\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Arch\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Version\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Repository\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Size<\/code><\/div>\n<div class=\"line number14 index13 alt1\"><code class=\"bash plain\">===============================================================================================================================<\/code><\/div>\n<div class=\"line number15 index14 alt2\"><code class=\"bash plain\">Removing:<\/code><\/div>\n<div class=\"line number16 index15 alt1\"><code class=\"bash spaces\">\u00a0<\/code><code class=\"bash plain\">kernel\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 x86_64\u00a0\u00a0\u00a0 2.6.32-358.el6\u00a0\u00a0\u00a0\u00a0 @anaconda-CentOS-201303050102.x86_64<\/code><code class=\"bash plain\">\/6<\/code><code class=\"bash plain\">.4\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 116 M<\/code><\/div>\n<div class=\"line number17 index16 alt2\"><\/div>\n<div class=\"line number18 index17 alt1\"><code class=\"bash plain\">Transaction Summary<\/code><\/div>\n<div class=\"line number19 index18 alt2\"><code class=\"bash plain\">===============================================================================================================================<\/code><\/div>\n<div class=\"line number20 index19 alt1\"><code class=\"bash plain\">Remove\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 1 Package(s)<\/code><\/div>\n<div class=\"line number21 index20 alt2\"><\/div>\n<div class=\"line number22 index21 alt1\"><code class=\"bash plain\">Installed size: 116 M<\/code><\/div>\n<div class=\"line number23 index22 alt2\"><code class=\"bash plain\">Is this ok [y<\/code><code class=\"bash plain\">\/N<\/code><code class=\"bash plain\">]: y<\/code><\/div>\n<div class=\"line number24 index23 alt1\"><code class=\"bash plain\">Downloading Packages:<\/code><\/div>\n<div class=\"line number25 index24 alt2\"><code class=\"bash plain\">Running rpm_check_debug<\/code><\/div>\n<div class=\"line number26 index25 alt1\"><code class=\"bash plain\">Running Transaction Test<\/code><\/div>\n<div class=\"line number27 index26 alt2\"><code class=\"bash plain\">Transaction Test Succeeded<\/code><\/div>\n<div class=\"line number28 index27 alt1\"><code class=\"bash plain\">Running Transaction<\/code><\/div>\n<div class=\"line number29 index28 alt2\"><code class=\"bash spaces\">\u00a0\u00a0<\/code><code class=\"bash plain\">Erasing\u00a0\u00a0\u00a0 : kernel-2.6.32-358.el6.x86_64\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 1<\/code><code class=\"bash plain\">\/1<\/code><\/div>\n<div class=\"line number30 index29 alt1\"><code class=\"bash spaces\">\u00a0\u00a0<\/code><code class=\"bash plain\">Verifying\u00a0 : kernel-2.6.32-358.el6.x86_64\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 1<\/code><code class=\"bash plain\">\/1<\/code><\/div>\n<div class=\"line number31 index30 alt2\"><code class=\"bash plain\">Removed:<\/code><\/div>\n<div class=\"line number32 index31 alt1\"><code class=\"bash spaces\">\u00a0\u00a0<\/code><code class=\"bash plain\">kernel.x86_64 0:2.6.32-358.el6\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Complete!<\/code><\/div>\n<div class=\"line number33 index32 alt2\"><code class=\"bash plain\">[root@dev ~]<\/code><code class=\"bash comments\">#<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/li>\n<li><strong>Update YUM Configuration to Automatically Remove Old Kernels:<\/strong><span class=\"Apple-converted-space\">\u00a0<\/span>Once we have the old CentOS Linux kernels removed we should now update the yum.conf file located in the \/etc directory on CentOS Linux to automatically remove the oldest kernel every time a new kernel is installed. Again the minimum you should set the install_only limit is two so you can always roll back to the older kernel is need be. Use your favorite editor such as \u201cvi\u201d to edit the \/etc\/yum.conf file and modify the install_only configuration line from the default 5 to 2 as shown in the below examples.<strong>Default yum.conf install_only Configuration:<\/strong>\n<div>\n<div id=\"highlighter_987687\" class=\"syntaxhighlighter nogutter  bash\">\n<table border=\"0\" cellspacing=\"0\" cellpadding=\"0\">\n<tbody>\n<tr>\n<td class=\"code\">\n<div class=\"container\">\n<div class=\"line number1 index0 alt2\"><code class=\"bash plain\">installonly_limit=5<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<p><strong>Default yum.conf install_only Configuration:<\/strong><\/p>\n<div>\n<div id=\"highlighter_179865\" class=\"syntaxhighlighter nogutter  bash\">\n<table border=\"0\" cellspacing=\"0\" cellpadding=\"0\">\n<tbody>\n<tr>\n<td class=\"code\">\n<div class=\"container\">\n<div class=\"line number1 index0 alt2\"><code class=\"bash plain\">installonly_limit=2<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/li>\n<li><strong>Verify CentOS Linux \/boot Directory Free Disk Space:<\/strong><span class=\"Apple-converted-space\">\u00a0<\/span>As you can see in the output below there is 42MB of disk space available even after using \u201cyum update\u201d to update packages that included a new kernel.\n<div>\n<div id=\"highlighter_63636\" class=\"syntaxhighlighter nogutter  bash\">\n<table border=\"0\" cellspacing=\"0\" cellpadding=\"0\">\n<tbody>\n<tr>\n<td class=\"code\">\n<div class=\"container\">\n<div class=\"line number1 index0 alt2\"><code class=\"bash plain\">[root@dev ~]<\/code><code class=\"bash comments\"># df -kh<\/code><\/div>\n<div class=\"line number2 index1 alt1\"><code class=\"bash plain\">Filesystem\u00a0\u00a0\u00a0\u00a0\u00a0 Size\u00a0 Used Avail Use% Mounted on<\/code><\/div>\n<div class=\"line number3 index2 alt2\"><code class=\"bash plain\">\/dev\/sda3<\/code>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <code class=\"bash plain\">228G\u00a0\u00a0 22G\u00a0 194G\u00a0 11% \/<\/code><\/div>\n<div class=\"line number4 index3 alt1\"><code class=\"bash plain\">tmpfs\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 1.9G\u00a0\u00a0\u00a0\u00a0 0\u00a0 1.9G\u00a0\u00a0 0% <\/code><code class=\"bash plain\">\/dev\/shm<\/code><\/div>\n<div class=\"line number5 index4 alt2\"><code class=\"bash plain\">\/dev\/sda1<\/code>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <code class=\"bash plain\">99M\u00a0\u00a0 53M\u00a0\u00a0 42M\u00a0 57% <\/code><code class=\"bash plain\">\/boot<\/code><\/div>\n<div class=\"line number6 index5 alt1\"><code class=\"bash plain\">[root@dev ~]<\/code><code class=\"bash comments\">#<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/li>\n<\/ol>\n<p>The end result will be that disk space for the \/boot directory should always be under control. In my personal opinion the \/boot directory should always be installed with more than 100MB of space so you can keep numerous older kernels or kernels for different tasks but many times you might take over administration of a server that is already configured and running.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Tonight when upgrading a CentOS Linux server it was noted by YUM that 15MB more disk space was needed to upgrade grub and the kernel itself. Below are four quick steps to verify what kernels are installed, install yum-utils if it is not installed already, delete previous kernels and set YUM to remove old kernels [&#8230;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5,4,17],"tags":[],"_links":{"self":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/4564"}],"collection":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=4564"}],"version-history":[{"count":1,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/4564\/revisions"}],"predecessor-version":[{"id":4565,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/4564\/revisions\/4565"}],"wp:attachment":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=4564"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=4564"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=4564"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}