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Zcentric

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sys-admin

  1. Dynamic haproxy config in SaltStack

    If you are anything like me, you like to over utilize haproxy. Salt stack has a nice feature for files that allow you to add to them in different state files. Say you want to have a stock haproxy config but sick and …

  2. Monitor Salt with Monit

    Sometimes salt has the tendency to crash. So we can use monit to fix that problem This assumes you already have the EPEL repo installed yum install monit Now with monit installed we can edit the following config …

  3. guestfish problems with virt-filesystems

    I was trying to use guestfish to increase a qcow2 partition without booting live and fdisking and all that mess. So I tried to run it and was getting # virt-filesystems --long --parts --blkdevs -h -a disk.qcow2 …

  4. Openvswitch / KVM / Libvirt / Ubuntu / VLANs the right way

    There are a lot of old blog posts out there to getting KVM guests to use different vlans via openvswitch. There are a lot that tell you to create fake bridges or create the ports via ovs-vsctrl and add tell libvirt to …

  5. Get Mandos working in Ubuntu

    I’ve been doing a lot of playing around with full dis encryption. Now there’s one big problem when you do full disk encryption is when the server reboots you are left at a prompt to enter your password to …

  6. Verify user's password on the command line

    If there’s any chance you need to verify a user’s password on the command line and you are root you can use openssl with the info from /etc/shadow. So first we want to grab the entry from /etc/shadow cat …

  7. SPF DNS Lookup check for Nagios

    Did you know that there is a max number of DNS lookups that can be done for an SPF lookup. The number is 10 and that includes any a or mx records along with includes to different hosts. I noticed this when I ran a SPF …

  8. No more apt-get prompts

    Sometimes you might be installing a package and don’t want it to prompt at all. Apt will prompt you a lot sometimes if you just do an apt-get install packageName. For example If you want to install, if there are …

  9. grep only stderr from a command

    So sometimes you have a command where you want to only grep stderr. For example I use Cronic to manage all my cronjobs. It’s really nice since it sends a nicely formatted email back to you if a command returns …

  10. Remove internal hosts in postfix

    A proper way to setup your network is to have a postfix relay server sitting somewhere on your network that every other server has access to via port 25. Now your relay server(s) are the only ones that should have …

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