Today I learnt

Today I learned about the dpkg_selections module in ansible. It is used to mark packages as hold, install … It can be used to implement some apt mark functionalities. Docs

Today I learned, how I can use Regex in location with proxy_pass. By default it is not supported by nginx, but we can capture the url with location and then pass it to the proxy_pass. Another solution is do a rewrite...break then do a proxy_pass. Source

Today I learned the difference between qemu:///system and qemu:///session. qemu:///system The system libvirtd instance qemu:///system launches the vms using the unpriviliges use qemu. And can grant the vm selective access to root owned resources. Access to qemu:///system is mediated using polkit and any user wanting to access it should provite the root password. By default users in the libvirt group have access to libvirtd (the group can be changed in polkit config) VMs are run as the default user qemu, and cannot access user files if the frontend application (virt-manager) is running another user. qemu:///session The user daemon qemu:///session is auto-launched if it’s not already running. each user has his own qemu:///session seperated. Most priviliges problems are related to networking use cases. The default networking mode is the usermode networking (SLIRP) (ip stack in the user space). Another option is to access bridged networking mode, through setuid script qemu-bridge-helper. More information

Today I learned about Qemu overlay storage images. To create an overlay image from a backing image we use the following command: qemu-img create -o backing_file=img1.raw,backing_fmt=raw -f qcow2 img1.cow Then we can boot from the new image, and changes to its filesystem will be recorded in the overlay image. qemu-system-x86_64 img1.cow The backing image absolute path is stored in the new image, so changing the its path require manual entervention. source

Today I learned about Windows filesystems(NTFS, FAT32 and exFAT), and the differences between them. | ** NTFS ** | The most modern (permissions, journaling, encryption, quota, hard links…), has no limits for file and partition sizes, and less universal (RO by default on Unix) | | ** FAT32 ** | The oldest, lightweight, 4GB max file size and 8TB max partition size, universal i.e supported by most platforms | | ** exFAT ** | Newer than FAT32, lightweight, same FAT32 use cases with larger limits | ...

Today I learned about the Reveal.js available default themes. Name Effect black Black background, white text, blue links (default) white White background, black text, blue links league Gray background, white text, blue links beige Beige background, dark text, brown links sky Blue background, thin dark text, blue links night Black background, thick white text, orange links serif Cappuccino background, gray text, brown links simple White background, black text, blue links solarized Cream-colored background, dark green text, blue links blood Dark background, thick white text, red links moon Dark blue background, thick grey text, blue links Source

Today I learned how to connect to a remote docker daemon using SSH and key authentication. DOCKER_HOST=ssh://“ssh://user@remotehost” docker-compose up -d This can be specified in a context