Perpetually incomplete
To check if you can run hosted hypervisors run:
cat /sys/module/kvm_intel/parameters/nested
If it returns ‘Y’ you are good to go, and actually don’t need this article, if it returns ‘N’ you can enable nested virtualization for the current boot
Continue reading “Linux Enable KVM guest hypervisors (nested hypervisors)”
If you are having problems with apt and IPv6 a temporary solution is to use the option ‘Acquire::ForceIPv4=true’ by appending ‘-o Acquire::ForceIPv4=true’ at the end of the apt command.
apt-get update -o Acquire::ForceIPv4=true
If you want a more permanent solution you can disable the usage of IPv6 with apt altogether with:
echo 'Acquire::ForceIPv4 "true";' | tee /etc/apt/apt.conf.d/99force-ipv4
https://unix.stackexchange.com/questions/9940/convince-apt-get-not-to-use-ipv6-method
Trailing in the deeps of the interwebs, I found an interesting Post, It teaches how to disable the root check for the VLC media player.
As some may know VLC rightfully refuses to run as root, and why you would want to run a video player as root is beyond me, but the post explain in some detail how to use a hex editor to search and alter the call to the ‘geteuid()’ function to a call of the ‘getppid()’ function effectively neutering the root check.
Continue reading “Bad Idea of the day, Disabling VLC root check”
If you run a lot of Virtual Machines using qemu, you probably can save a lot of memory, at the expense of CPU cycles, by enabling Kernel Samepage Merging (KSM).
If you just want to test it and run only on the current boot run the following:
echo 1 > /sys/kernel/mm/ksm/run
After testing if you want to enable it permanently you can use systemd temporary files.
Continue reading “Enable KSM Centos7/Debian”
A Self-hosted installation of GitLab comes with an extremely interesting and useful tool that is disabled by default, the Mattermost chat server, think of it as a self-hosted and better Slack.
If you installed GitLab using the Omnibus package, the recommended way, you can enable it and set up a letsencrypt certificate in a few steps as described bellow.
Open the file ‘/etc/gitlab/gitlab.rb’ and find the line:
Continue reading “Enabling Mattermost on the Gitlab Instalation”
The installation of a self hosted Gitlab instance using SSL certificates from Let’sEncrypt on a Centos 7 is simple and straightforward.
Run as root the following, remember to change Gitlab.example.com with the domain you intend to use for your Gitlab installation
Continue reading “Gitlab on-premisses install + Let’s Encrypt”
Sometimes it’s interesting to get the hash of the head of the current git repository, with it you can check if you are running an up-to-date version or postfix it in URLs with ‘?version=(hash)’ so you won’t have problems with browser/proxies caches.
Continue reading “Get Git Head via PHP script”
If you’ve been bitten by the following bug during the installation of the certbot DNS auth plugin for route53.
---> Package python2-boto3.noarch 0:1.4.6-1.el7 will be installed
--> Processing Dependency: python2-s3transfer >= 0.1.10 for package: python2-boto3-1.4.6-1.el7.noarch
Package python2-s3transfer is obsoleted by python-s3transfer, but obsoleting package does not provide for requirements
--> Finished Dependency Resolution
Error: Package: python2-boto3-1.4.6-1.el7.noarch (epel)
Requires: python2-s3transfer >= 0.1.10
Available: python2-s3transfer-0.1.10-1.el7.noarch (epel)
python2-s3transfer = 0.1.10-1.el7
Continue reading “Install python2-certbot-dns-route53 centos 7”
One annoying “feature” of the windows 10 NFS client is that by default the anonymous user uid and gid is set to -2, and so you can create new files and directories on your NFS server, but you can’t edit or remove existing files.
To fix it, you can paste the code bellow in a text file and save it with a ‘.reg’ extension, run it and reboot the machine.
Continue reading “Enable(fix) write permissions on a NFS share mounted on Windows 10”
If you want to give the zswap kernel extension a try you can enable it just for the current boot with the following
echo 1 > /sys/module/zswap/parameters/enabled
If you want to make the change permanent, it’s simple to do it adding a kernel boot parameter on the grub bootloader
Continue reading “Enable zswap in Linux”