When we upload an image using openstack image create --file, the image file will be transferred to image storage backend through glance api servers. If the image size is huge, the upload process might take time sometimes ends in failure. Glance API might become the bottleneck if multiple huge images are uploaded at the same time. To overcome glance api servers bottleneck, we could instead directly upload the image to ceph following the below procedure.

We can confirm what build flags are enabled at build time by checking the below places. Default build flags in the source code’s Makefile or build tool’s declaration files (CMakeLists.txt). In the debian/rules file. The build system at build time (dh). As deb packages on different Ubuntu releases have different versions, it is necessary to verify the build flags in deb package and upstream package within the same version. For example, below are the process to verify the build flags of ceph package in Ubuntu 22.

Problem Given a JSON data below, output the data in CSV/TSV format. [ { "id": 0, "data": [0, 1, 2] }, { "id": 1, "data": [1, 2, 3] }, { "id": 2, "data": [3, 4, 5] } ] Expected output. "0\t0,1,2" "1\t1,2,3" "2\t3,4,5" How to JQ provides @tsv and @csv function that convert data to the corresponding format. Each row of the output CSV table should be formated to an array type before these functions can consume.

For many years, I have maintained my blog on blogger.com. Though I find it is a really-easy-to-use blogging platform, I am still unsatisfied with the lack of many necessary features. Many of my frustration when using blogger.com are: It does not allow me to easily format code. I need to use a thirdparty to help format my code. I would copy the result to generated html of my article. That process is tedious and error-prone.

From Wikipedia of Open Virtualization Format, I learned that an the ova file is just a tar file of ovf directory. So I went open a Windows 10 Developer Evaluation ova file to see what exist inside it. $ tar -tf WinDev2001Eval.ova WinDev2001Eval.ovf WinDev2001Eval-disk001.vmdk WinDev2001Eval.mf So inside the ova file includes A virtual machine specification definition .ovf file A hash checksum .mf file A disk image in .vmdk image As qemu-img supports vmdk as disk image file, we actually could convert vmdk file to any other format that we like.

In Linux Operating system, full disk encryption could be achieved by various solutions: encryptfs, dm-crypt… While a step-by-step setup of disk/partition encryption can be referred from official documentation, integration disk encryption with Key Management solution like Hashicorp Vault is unobvious. Fortunately, there are a package named vaultlocker in Ubuntu Universe repository that ease this integration. I decided to spend my free time to make cryptsetup work with Vault. Notes: A similar request has been made to Cryptsetup but it goes outside of cryptsetup so it was closed.

Background My old desktop becomes sluggish as I deploy multiple test environment on it. As I also use various desktop applications for my daily works on the same desktop machine, sometimes resource insufficiency freeze the all the applications, interfering my work flows. I am always a fan of small low-energy NUC devices so I take this chance to buy a new NUC device solve my resource issue. Before buying new device, I had some considerations for a NUC.

Enviro pHat is an low-cost environmental sensing boards that let you measure temperature, light color, motion and analog sensors. The accompanied python SDK makes writing program to get data from enviro pHat as easy as pie. Enviro pHat could be used in combination with RaspPi zero to become a simple room conditions monitoring sensing board. With grafana and prometheus, it looks so easy to at least build a dashboard for environ pHat sensors data, so I decided to build a enviro pHat dashboard.

Besides managing bare metal machines, MAAS (Metal as a Service) can also manage KVM guests as long as those machines are boot from network PXE. This feature allow us to efficiently manage local computing resources, while at the same time, leverage JuJu for automatically middle ware deployment. In this post, I will detail steps to manage KVM guest machines using MaaS. System diagram MaaS Managed Machine: MaaS Virtual Machine creates other Virtual machines through KVM Pod.

Juju User JuJu has an internal user framework, which supports sharing of controllers and models. Using JuJu user feature, a sysadmin could separated users for controllers as in multiple clouds deployment or for users as in multiple systems deployment. Each juju user can have its own permissions at application, model, or controller layer. This separation of responsibilities allow multiple users to manage multiple infrastructures with a clear border of responsibilities.