If you have requested a single host from beaker, the following one liner will tell the hostname for it.
bkr job-results $( bkr job-list -o $USER --unfinished | jq -r "." ) | xpath -q -e string\(/job/recipeSet/recipe/roles/role/system/@value\)
This requires jq and xpath, as well as the beaker command line packages.
For me on Fedora 33 the packages are:
Yocto takes up a lot of space when it builds. If the /home partition is 30 GB or smaller, I am going to fill it up. The systems I get provisioned from Beaker are routinely splitting their disks between / and /home. These are both logical volumes in the same volume group. This is easy to merge.
In order to merge them I find myself performing the following steps.
I then modify /etc/fstab so that the /home entry is now pointing to /althome. If I have done any work in /home/ayoung (almost always) I have to copy it to the new /home partition
cp /althome/ayoung /home/ayoung
Once the home volume has been cleared, I can reclaim the space. The following lines will vary depending on the name of the machine.
lvresize -L +32.48G /dev/rhel_hpe-moonshot-02-c07/root
I am explicitly reclaiming the size of the /home volume, which in this case is 32.48 GB.
A little bit of foresight can obviously avoid this problem; properly allocate the disks according to the workload. Requesting a machine with more disk is also an option.
But sometimes we have to fix mistakes.
Note that I use the lvdisplay command to see the names of the volumes.
In order to make use of the new space, I have to resize the file system. Since it is XFS, I use the xfs_grow command. I want the full size, so I don’t need to pass a parameter.
I’m trying to run a Jamulus server . I got it running, but the latency was high. My first step was to add the real time kernel from CCRMA.
CCRMA no longer ships a super-package for core. The main thing missing seems to be the rtirq package.
- installed the ccrma repo file.
- installed the real time Kernel
- Set the RT kernel as the default.
- installed the rtirq scripts rpm
- enabler the systemd module for rtirq
- cloned the Jamulus repo from git
- configure, built, and installed Jamulus from the sources
- added a systemd module for Jamulus
- set selinux to permissive mode (starting Jamulus failed without this)
- started Jamulus
- ensured I could connect to it
- stopped jamulus
- set selinux to enforcing mode
- restarted Jamulus from systemctl
- connected from my desktop to the Jamulus server
It does not seem to have much impact on the latency I am seeing. I think that is bound more by network.
I have a server that I want to run the Real Time Kernel from CCRMA. Once I followed the steps to get the kernel installed, I had to reboot to use it.
Rebooting on a server with a short timeout for grub is frustrating.
Since the Fedora Kernel is installed, and I want to be able to run it as a backup kernel, I had to figure out how to change the default Kernel for Grub2. Most of the docs out there assume that you can list the menu-items in the grub2 config file, but that is a thing of the past. The lines are now auto-generated from a regex match of the places where one might place the vmlinuz files.
I ended up booting the machine and looking at the grub menu, which showed three Kernels installed; two Fedora Kernels and the RT from CCRMA. The RT Kernel was the second one on the list. But Grub is 0 relative, so to set the default Kernel:
The next time it booted, it was set to the RT kernel;
$ uname -r
A graphical User interface has the potential ability to guide users on their journey from n00b13 to power user. If a user has never used a system before, the graphical user interface can provide a visual orientation to the system that is intuitive and inviting.
Once a user starts to depend on a system and use it regularly, they often want to automate tasks performed in that system.
I am reminded of these principals as I start making use of my company’s beaker server. I need short term access to machines of various architectures develop and test our Yocto based coding efforts.
We use Beaker to allocate and loan computer hardware. If you want to talk to it via the comand line, you can use the bkr executable. Some of the information comes back as json, but beaker tends to speak xml. To look up a host name from a job, you need to be able to parse the xml. To do that, I used the xq execuable from the python yq package. Yes, x and y.
I installed yq via pip. That puts both the xq and yq executablees into ~/.local/bin.
If i know the job ID, I can parse it using the following syntax.
bkr job-results 'J:5078388' | xq -r ".job | .recipeSet | .recipe| .task | . | .roles | .role | .system | .\"@value\""
UPDATE: So here is a useful script that makes use of bkr, jq, and xq to list the hostnames of the hosts I currently have on loan from beaker.
for job in $( bkr job-list -o $USER --unfinished | jq -r '.' ) ; do bkr job-results $job | xq -r ".job | .recipeSet | .recipe| .task | . | .roles | .role | .system | .\"@value\"" ; done
While reviewing the comments on the Ironic spec, for Secure RBAC. I had to ask myself if the “project” construct makes sense for Ironic. I still think it does, but I’ll write this down to see if I can clarify it for me, and maybe for you, too.
“I can do any thing. I can’t do everything.”
The sheer number of projects and problem domains covered by OpenStack was overwhelming. I never learned several of the other projects under the big tent. One project that is getting relevant to my day job is Ironic, the bare metal provisioning service. Here are my notes from spelunking the code.
The key piece of persisted data in an DHCP server is the lease. A lease is a the mapping between a MAC address and an IP address, limited in time. A Lease typically has a start time and an end time, but can be renewed. Because I am still living in an IPV4 world, I have to deal with arbitrarily small pools of IP addresses. Thus, the design needs to strike the balance between static and dynamic: a machine should generally get back the same IP address each time. However, if addresses get tight, address reuse should be aggressive.