Skip to main content

Regex foo - checking crashkernel value

I need to check the crashkernel setting on all of my hosts.

The issue(s):
  • crashkernel=<blah> can exist anywhere in the string 
  • there may be several iterations of a boot entry which contains crashkernel
In this example, I purposely used a grub.conf which had 2 different crashkernel values to demonstrate how to change the enumeration of the test (either 1 or 2).

[root@rhvsrv01 ~]# egrep '^[[:space:]]*kernel /vmlinuz.*crashkernel=' /boot/grub/grub.conf | sed -r '1!d;s/.*crashkernel=([[:graph:]]+).*/\1/'
auto
 
[root@rhvsrv01 ~]# egrep '^[[:space:]]*kernel /vmlinuz.*crashkernel=' /boot/grub/grub.conf | sed -r '2!d;s/.*crashkernel=([[:graph:]]+).*/\1/'
16M@128M

[root@rhvsrv01 ~]# grep vmlinuz /boot/grub/grub.conf | grep -v \#
    kernel /vmlinuz-2.6.32-358.2.1.el6.x86_64 ro root=/dev/mapper/VolGroup00-LogVol01 rd_NO_LUKS LANG=en_US.UTF-8 rd_NO_MD SYSFONT=latarcyrheb-sun16 crashkernel=auto rd_LVM_LV=VolGroup00/LogVol01 rd_LVM_LV=VolGroup00/LogVol00  KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rhgb quiet elevator=deadline processor.max_cstate=1
    kernel /vmlinuz-2.6.32-358.el6.x86_64 ro root=/dev/mapper/VolGroup00-LogVol01 rd_NO_LUKS LANG=en_US.UTF-8 rd_NO_MD SYSFONT=latarcyrheb-sun16 crashkernel=16M@128M rd_LVM_LV=VolGroup00/LogVol01 rd_LVM_LV=VolGroup00/LogVol00  KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rhgb quiet


If you need to append something to the line starting with "    kernel"
  sed -i -e '/^.kernel/ s/$/ transparent_hugepage=never/' /boot/grub/grub.conf
 
 

Labels

Labels:

Comments

Post a Comment

Popular posts from this blog

P2V using dd for KVM-QEMU guest

Preface: I have certainly not exhaustively tested this process.  I had a specific need and found a specific solution that worked. Situation:  I was issued a shiny new laptop running Red Hat Enterprise Linux 7 (with Corp VPN, certs, Authentication configuration, etc...)  The image was great, but I needed more flexibility on my bare metal.  So, my goal was to P2V the corporate image so I could just run it as a VM. * Remove corporate drive and install new SSD * install corp drive in external USB-3 case * Install RHEL 7 on new SSD * dd old drive to a disk-image file in a temp location which will be an image which is the same size as your actual drive (unless you have enough space in your destination to contain a temp and converted image) * convert the raw disk-image to a qcow file while pushing it to the final location - this step should reduce the disk size - however, I believe it will only reduce/collapse zero-byte blocks (not just free space - i.e. if you de...
1 comment
Read more

Sun USS 7100 foo

TIP: put ALL of your LUNs into a designated TARGET and INITIATOR group when you create them.  If you leave them in the "default" group, then everything that does an discovery against the array will find them :-( I'm struggling to recognize a reason that a default should even be present on the array. Also - who, exactly, is Sun trying to kid.  The USS is simply a box.. running Solaris .. with IPMP and ZFS.  Great.  If you have ever attempted to "break-in" or "p0wn" your IBM HMC, you know that there are people out there that can harden a box - then.. there's Sun.  After a recent meltdown at the office I had to get quite intimate with my USS 7110 and learned quite a bit.  Namely: there's a shell ;-) My current irritation is how they attempt to "warn you" away from using the shell (my coverage expired a long time ago to worry about that) and then how they try to hide things, poorly. I was curious as to what version of SunOS it ...
1 comment
Read more

"Error getting authority: Error initializing authority: Could not connect: No such file or directory (g-io-error-quark, 1)"

"Error getting authority: Error initializing authority: Could not connect: No such file or directory (g-io-error-quark, 1)" One issue that may cause this to arise is if you managed to break your /etc/fstab We had an engineer add a line with the intended options of "nfsvers=3" but instead added "-onfsvers=3" and it broke the system fairly catastrophically.
Post a Comment
Read more