RHEL: Adding Disk Space
- Jul
- 31
- Posted by TKH Specialist
- Posted in Uncategorized
So your Disk is getting full or worse already full. Here’s a step-by-step approach to troubleshoot and resolve this issue: First, verify the current state of your volume group: vgdisplay vc_name This will show you the details of the ‘rhel’ volume group, including free space. Check the status of the new disk: Ensure that /dev/sdb […]
read morePut A TimeStamp on Bash History
- Aug
- 23
- Posted by TKH Specialist
- Posted in bash, History, linux
Sometimes, it is very helpful to have a timestamp on bash history, that way it’s easier to know the exact time a command was executed. To put a timestamp on history, run the following command; HISTTIMEFORMAT=”%d/%m/%y %T ” That’s all. Next time you run the history command, the history will display with timestamp. Hope someone […]
read moreKerberizing RHEL Server
- Jun
- 13
- Posted by TKH Specialist
- Posted in RedHat 6, RedHat 7, System Administration
Notes from Plone… yum install krb5-workstation pam_krb5 -y # if krb5.conf is present we should get a fresh copy mv /etc/krb5.conf /etc/krb5.conf.bak yum reinstall krb5-libs -y sed -ie ‘s/example.com/FQDN/g’ /etc/krb5.conf sed -ie ‘s/EXAMPLE.COM/FQDN/g’ /etc/krb5.conf fqdn=`hostname –fqdn`; echo ” ank -randkey host/$fqdn@FQDN ktadd -k /etc/krb5.keytab host/$fqdn@FQDN “; — OR — kadmin netid/admin@FQDN addprinc -randkey host/$fqdn ktadd […]
read moreDon’t Panic Kernel!
- May
- 17
- Posted by TKH Specialist
- Posted in redhat, System Administration
You do your best to keep your systems running, but eventually something is going to happen (read you are going to do something) that leads to a Kernel Panic. Every System Administrator fears a Kernel Panic at some point in their career, but it is never a good idea to panic over one! Here are […]
read moresystemd commands, hints and cheatsheet
- Apr
- 15
- Posted by TKH Specialist
- Posted in Cheat Sheets, RedHat 7, System Administration
List all running services # systemctl Start/stop or enable/disable services Activates a service immediately: # systemctl start foo.service Deactivates a service immediately: # systemctl stop foo.service Restarts a service: # systemctl restart foo.service Shows status of a service including whether it is running or not: # systemctl status foo.service Enables a service to be started […]
read moreDisk Woes
- Sep
- 10
- Posted by TKH Specialist
- Posted in System Administration, Workstation
I hope to never use this document again but thought it worth documenting in case someone else has need of the information. I powered my desktop off for a planned power outage. When I powered it back on the system failed to boot reporting either “Error 17” or “Error 25”, in short the software raid […]
read moreUnresponsive VMware Images
- Sep
- 10
- Posted by TKH Specialist
- Posted in System Administration
Over the past week I have had two vmware images become unresponsive. When trying to access the images via the vmware console any action reports: rejecting I/O to offline device A reboot fixes the problem, however for a Linux guy that isn’t exactly acceptable. Upon digging a little deeper it appears the problem is with […]
read more6GB free = 100% disk usage?!
- May
- 15
- Posted by TKH Specialist
- Posted in LVM, redhat, System Administration
What to do when you have plenty of available disk space but the system is telling you the disk is full?! I was working on a server migration, moving 94GB of user files from the old server to the new server. Since we aren’t planning on seeing a lot of growth on the new server, […]
read moreCleaning Up Memory Usage
- May
- 06
- Posted by TKH Specialist
- Posted in System Administration
I noticed my Ubuntu desktop was using a rather large portion of available memory. I usually have a lot running on my system, multiple terminals, background jobs, etc so this is nothing unusual. Today however I noticed my system was sluggish so I started digging. Memory use was near 100%. I closed all of my […]
read moreDenyhosts Assists
- Apr
- 10
- Posted by TKH Specialist
- Posted in Security, System Administration
Every so often a legitimate user will get blocked by deny hosts. When this happens you can re-enable their access with these 8 simple steps (UPDATE: or use the faster version, see below): Stop DenyHosts # service denyhosts stop Remove the IP address from /etc/hosts.deny Edit /var/lib/denyhosts/hosts and remove the lines containing the IP address. […]
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