Visiting UK again — Bletchley Park and Cambridge Beer Festival

For some time I had “visit Bletchley Park” on my ‘places to visit’ list. Some people told me that there is nothing interesting to see, some said that I should definitely go there. So I will. And will also grab some beers at Cambridge Beer Festival like three years ago.

Due to some family duties my visit will be short — landing on Saturday (21st May) and departing on Wednesday (25th May). First Bletchley park and then Cambridge from Sunday evening.

Plans are simple: walk, see old computers, walk, visit long time no see friends, walk, see not so old computers, maybe play some Ingress, meet other friends, drink some beers, exchange some hardware, buy some hardware etc.

This time will skip visiting Linaro office — they moved somewhere outside of Cambridge so it takes too much time to get there just to say “hi” and drink tea.

As usual I will be online so catch me via Hangouts, Telegram, Facebook, mail or call me if you want to meet.

My workflow for building big sets of RPM packages

In last months I did two rebuilds: NodeJS 4.x in Fedora and OpenStack Mitaka in CentOS. Both were targeting AArch64 and both were not done before. During latter one I was asked to write about my workflow, so will describe it with OpenStack one as base.

identify what needs to be done

At first I had to figure out what exactly needs to be built. Haïkel Guémar (aka number80) pointed me to openstack-mitaka directory on CentOS’ vault where all source packages are present. Also told me that EPEL repository is not required which helped a lot as it is not yet built for CentOS.

structure of sources

OpenStack set of packages in CentOS is split into two parts: “common” shared through all OpenStack versions and “openstack-mitaka” containing OpenStack Mitaka packages and build dependencies not covered by CentOS itself or “common” directory.

prepare build space

I used “mockchain” for such rebuilds. It is simple tool which does not do any ordering tricks just builds set of packages in given order and do it three times hoping that all build dependencies will be solved that way. Of course what got built once is not tried again.

To make things easier I used shell alias:

alias runmockchain mockchain -r default -l /home/hrw/rpmbuild/_rebuilds/openstack/mockchain-repo-centos

With this I did not have to remember about those two switches. Common call was “runmockchain –recurse srpms/*” which means “cycle packages three times and continue on failures”.

Results of all builds (packages and logs) were kept in “~/_rebuilds/openstack/mockchain-repo-centos/results/default/” subdirectories. I put all extra packages there to have all in one repository.

populate “noarch” packages

Then I copied x86-64 build of OpenStack Mitaka into “_IMPORT-openstack-mitaka/” to get all “noarch” packages for satisfying build dependencies. I built all those packages anyway but having them saved me several rebuilds.

extra rpm macros

When I started first build it turned out that some Python packages lack proper “Provides” fields. I was missing newer rpm build macros (“%python_provide” was added after Fedora 19 which was base for RHEL7). Asked Haïkel and added “rdo-rpm-macros” to mock configuration.

But had to scrap everything I built so far.

surprises and failures

Building big set of packages for new architecture most of time generate failures which were not present with x86-64 build. Same was this time as several build dependencies were missing or wrong.

packages missing in CentOS/aarch64

Some were from CentOS itself — I told Jim Perrin (aka Evolution) and he added them to build queue to fill gaps. I built them in meantime or (if they were “noarch”) imported into “_IMPORT-extras” or “_IMPORT-os” directories.

packages imported from other CBS tags

Other packages were originally imported from other tags at CBS (CentOS koji). For those I created directory named “_IMPORT-cbs”. And again — if they were “noarch” I just copied them. For rest I did full build (using “runmockchain”) and they end in same repository as rest of build.

For some packages it turned out that they got built long time ago with older versions of build dependencies and are not buildable from current versions. For them I tracked proper versions on CBS and imported/built (sometimes with their build dependencies and build dependencies of build dependencies).

downgrading packages

There was a package “python-flake8” which failed to build spitting out Python errors. I checked how this version was built on CBS and turned out that “python-mock” 1.3.0 (from “openstack-mitaka” repository) was too new… Downgraded it to 1.0 allowed me to build “python-flake8” one (upgrading of it is in queue).

merging fixes from Fedora

Both “galera” and “mariadb-galera” got AArch64 support merged from Fedora and got built with “.hrw1” added into “Release” field.


I did whole build in “~/rpmbuild/_rebuilds/openstack/” directory. Extra folders were:

  • mockchain-repo-centos/results/default/_HACKED-by-hew/
  • mockchain-repo-centos/results/default/_IMPORT-cbs/
  • mockchain-repo-centos/results/default/_IMPORT-extras/
  • mockchain-repo-centos/results/default/_IMPORT-openstack-mitaka/
  • mockchain-repo-centos/results/default/_IMPORT-os/

Vault ones were copy of OpenStack source packages and their build dependencies. Hacked ones got AArch64 support merged from Fedora. Both “extras” and “os” directories were for packages missing in CentOS/AArch64 repositories. CBS one was for source/noarch packages which had to be imported/rebuilt because they came from other CBS tags.

status page

In meantime I prepared web page with build results so anyone interested can see what builds, what not and check logs, packages etc. It has simple description and then table with list of builds (data can be sorted by clicking on column headers).


Whole job would take much more time if not help from CentOS developers: Haïkel Guémar, Alan Pevec, Jim Perrin, Karanbir Singh and others from #centos-devel and #centos-arm IRC channels.

How to speed up mock

Fedora and related distributions use “mock” to build packages. It creates chroot from “root cache” tarball, updates it, installs build dependencies and runs build. Similar to “pbuilder” under Debian. Whole build time can be long but there are some ways to get it faster.

kill fsync()

Everytime something calls “fsync()” storage slow downs because all writes need to be done. Build process goes in a chroot which will be removed at the end so why bother?

Run “dnf install nosync” and then enable it in “/etc/mock/site-defaults.cfg” file:

config_opts['nosync'] = True

local cache for packages

I do lot of builds. Often few builds of same package. And each build requires fetching of RPM packages from external repositories. So why not cache it?

In LAN I have one machine working as NAS. One of services running there is “www cache” with 10GB space which I use only for fetching packages — both in mock and system and I use it on all machines. This way I can recreate build chroot without waiting for external repositories.

config_opts['http_proxy'] = 'http://nas.lan:3128'

Note that this also requires editing mock distribution config files to not use “mirrorlist=” but “baseurl=” instead so same server will be used each time. There is a script to convert mock configuration files if you go that way.

decompress root cache

Mock keeps tarball of base chroot contents which gets unpacked at start of build. By default it is gzip compressed and unpacking takes time. On my systems I switched off compression to gain a bit at cost of storage:

config_opts['plugin_conf']['root_cache_opts']['compress_program'] = ""
config_opts['plugin_conf']['root_cache_opts']['extension'] = ""


If memory is not an issue then tmpfs can be used for builds. Mock has own plugin for it but I do not use it. Instead I decide on my own about mounting “/var/lib/mock” as tmpfs or not. Why? I only have 16GB ram in pinkiepie so 8-12GB can be spent on tmpfs while there are packages which would not fit during build.

parallel decompression

Sources are compressed. Nowadays CPU has more than one core. So why not using it with multithreaded gzip/bzip2 depackers? This time distro file (like “/etc/mock/default.cfg” one) needs to be edited:

config_opts['chroot_setup_cmd'] = 'install @buildsys-build /usr/bin/pigz /usr/bin/lbzip2'
config_opts['macros']['%__gzip'] = '/usr/bin/pigz'
config_opts['macros']['%__bzip2'] = '/usr/bin/lbzip2'

extra mockchain tip

For those who use “mockchain” a lot this shell snippet may help finding which packages failed:

for dir in *
    if [ -e $dir/fail ];then
        rm $dir/fail
        mv $dir _fail-$dir


With this set of changes I can do mock builds faster than before. Hope that it helps someone else too.


Six years ago I was one of first members of project which later got “Linaro” name. Today I am back. But in different form.

On 30th April 2010 I got email titled “Welcome to Linaro” and became software engineer at Linaro. Time shown that it was done in a way which helped to start project but was not liked by member companies. The plan was to leave in October 2012 but due to someone’s decision I stayed until May 2013.

Today I got “Linaro Assignee On-Boarding” email which means that I am still officially software engineer at Red Hat but assigned to work at Linaro. Same as people from other member companies.

I wonder will I get my unofficial title “main complainer at Linaro” back or do I have to deserve it again ;D

Failed to set MokListRT: Invalid Parameter

Somehow I managed to break UEFI environment on APM Mustang. As a result I was not able to enter boot manager menu nor UEFI shell. All I had was booting to 0001 boot entry (which was just installed Fedora 24 alpha).

After reboot I scrolled a bit to take a look at firmware output:

X-Gene Mustang Board
Boot firmware (version 1.1.0 built at 14:50:19 on Oct 20 2015)
TianoCore 1.1.0 UEFI 2.4.0 Oct 20 2015 14:49:32
CPU: APM ARM 64-bit Potenza Rev A3 2400MHz PCP 2400MHz
     SOC 2000MHz IOBAXI 400MHz AXI 250MHz AHB 200MHz GFC 125MHz
Board: X-Gene Mustang Board
Slimpro FW:
        Ver: 2.4 (build 2015/04/22)
        PMD: 950 mV
        SOC: 950 mV
Failed to set MokListRT: Invalid Parameter

Here screen got cleared instantly and grub was shown. I booted into one of installed systems and started playing with EFI boot manager:

17:38 root@pinkiepie-rawhide:~$ efibootmgr 
BootCurrent: 0001
Timeout: 0 seconds
BootOrder: 0001,0004,0000
Boot0000  Fedora rawhide
Boot0001* Fedora
Boot0004* Red Hat Enterprise Linux

Note “0 seconds” timeout. I changed it to 5s (efibootmgr -t 5), rebooted and UEFI menu appeared again:

TianoCore 1.1.0 UEFI 2.4.0 Oct 20 2015 14:49:32
CPU: APM ARM 64-bit Potenza Rev A3 2400MHz PCP 2400MHz
     SOC 2000MHz IOBAXI 400MHz AXI 250MHz AHB 200MHz GFC 125MHz
Board: X-Gene Mustang Board
Slimpro FW:
        Ver: 2.4 (build 2015/04/22)
        PMD: 950 mV
        SOC: 950 mV
The default boot selection will start in   5 seconds
[1] Fedora rawhide
[2] Red Hat Enterprise Linux
[3] Fedora
[4] Shell
[5] Boot Manager
[6] Reboot
[7] Shutdown

So I can boot whatever I want again ;D

Why my device is not supported by distributions

During weekend I was in Puck, Poland at small conference called “Zimowisko linuksowe” (Linux winter camp) where I had a talk called “Dlaczego moje urządzenie nie jest obsługiwane przez dystrybucje” (Why my device is not supported by distributions).

In talk I presented how distributions (Debian, Fedora) handle ARM devices (one kernel for all, one image for all) and why it does not fit Raspberry/Pi or Chromebook. Also mentioned Roseapple/Pi as an example of how not to make support for device.

There were questions about suggested boards (most of people knew Raspberry/Pi and one or two other by name) and ARM powered laptops other than Chromebooks.

And then we went to celebrate birthdays of few friends who had them on same day.

You can download presentation in Polish or English (translation was requested by few folks from IRC after I annouced that there will be such talk).