CommonQuestions

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= Kernel =

== I want to use the most recent kernel on my Ubuntu ==

Canonical has a [[PPA|https://launchpad.net/~canonical-kernel-team/+archive/ubuntu/ppa]] that contains the most upstream kernel available for you to test. It might not be well tested, neither ready for production ready, but, it might help you to do some tests with a recent kernel.

In order to use it, you should add the PPA repository to your source list file, as:

{{{
   deb http://ppa.launchpad.net/canonical-kernel-team/ppa/ubuntu YOUR_UBUNTU_VERSION_HERE main
   deb-src http://ppa.launchpad.net/canonical-kernel-team/ppa/ubuntu YOUR_UBUNTU_VERSION_HERE main
}}}

Later, just install the most upstream release of your kernel.

For example, in order to install kernel 3.19 in vivid, I just did the following:

{{{
# cat <<EOF >> /etc/sources.list
deb http://ppa.launchpad.net/canonical-kernel-team/ppa/ubuntu vivid main
deb-src http://ppa.launchpad.net/canonical-kernel-team/ppa/ubuntu vivid main
EOF

# apt-get install linux-image-3.19.0-6-generic

# reboot
.....

# uname -a
Linux ubuntu1504 3.19.0-6-generic #6-Ubuntu SMP Mon Feb 23 10:49:25 UTC 2015 ppc64le ppc64le ppc64le GNU/Linux
}}}

General

What are the new features for each release?

What is the URL to download Ubuntu for Power?

What is the URL to download Ubuntu daily images?

How to build a new kernel?

The majority of users that are interested in building their own kernel are doing so because they have installed Ubuntu on their system and they wish to make a small change to the kernel for that system. In many cases the user just wants to make a kernel configuration change. Building a kernel for ppc64el is exactly the same as for amd64 architecture.

In order to do so, just follow the steps at https://wiki.ubuntu.com/Kernel/BuildYourOwnKernel

Installation & Configuration

How to Report an installation bug effectively?

It's important to add the log in the bug report. To get it you need:

  1. At the error message, choose "Back" button;
  2. Go to the item "Exit to shell"
  3. Get the file /var/log/syslog

How to use Ubuntu as a hypervisor?

  • Note Recommended 14.10 or later

Ubuntu is able to be used as a hypervisor, as an alternative to PowerKVM. Just install in bare metal (NV) it following the steps in Running Ubuntu non-virtualized on POWER8 After the installation you need:

  1. Install the missing virtualization packages:

    # sudo apt-get install qemu-user qemu-utils cloud-image-utils qemu-system-ppc qemu-slof libvirt-bin numactl

  2. Add the users that would be able to run virtual machines into the kvm group:

    # sudo usermod -a -G kvm <user>

  3. Disable the SMT:

    # sudo ppc64_cpu --smt=off

  4. Enable KVM module in the kernel (Add a line "kvm_hv" in /etc/modules in order to automatically load it after a reboot):

    # sudo modprobe kvm_hv

  5. Assure that you have the /usr/bin/qemu-system-ppc64le file, otherwise, create a link as follow. This is temporary, check [1]:

    # sudo ln -s qemu-system-ppc64 /usr/bin/qemu-system-ppc64le

  6. Allow apparmor to access the SLOF (firmware). This is temporary, check [2]:

    # echo "/usr/share/slof/** r," >> /etc/apparmor.d/abstractions/libvirt-qemu

  7. If you hit "failed to parse default acl file `/etc/qemu/bridge.conf", you need to edit (or create) file /etc/qemu/bridge.conf and add:

    allow br0

  8. If you hit "failed to create tun device: Operation not permitted", you need to set the setuid attribute:

    # chmod u+s /usr/lib/qemu/qemu-bridge-helper

[1] https://bugs.launchpad.net/ubuntu/+source/virt-manager/+bug/1374558
[2] https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/1374554

Apt-get is using IPv6 to download repository information and I don't have it. How do I force IPv4?

Just run the following command:

  • echo "Acquire::ForceIPv4 true;" > /etc/apt/apt.conf.d/99force-ipv4

Usage

How to search and get more information about a package in Ubuntu?

If you have Ubuntu installed on a machine, you can run the following command to grab the package version and details for the Ubuntu version you are using:

  • apt-cache search <package name>

On the other side, you can go to the web and look for the package on the Ubuntu webpage:

What are the build log for packages?

How to discover in which repository (main, universe, multiverse) a package is

Append the package name at https://launchpad.net/ubuntu/+source/, as (https://launchpad.net/ubuntu/+source/nmap for nmap). Look at the Component field.

How to upgrade a system to the most upgraded state, as from a beta to a GA release. (not migrating between major release as 14.04 -> 14.10)

Run the following commands:

  • sudo apt-get update
    sudo apt-get upgrade

How to enable the -proposed repository in ubuntu

In order to enable the proposed repositories, you can modify the software sources manually by adding the following line to /etc/apt/sources.list:

deb http://archive.ubuntu.com/ubuntu/ trusty-proposed restricted main multiverse universe

If you are using a port arch such as armhf/arm64/ppc64el you need to add the following line instead :

deb http://ports.ubuntu.com/ubuntu-ports trusty-proposed restricted main multiverse universe

Replace "trusty" with "vivid", "utopic", "precise", or "lucid" depending on which release you are on. It is recommended to enable selective upgrading from -proposed as described in the next section!

I want to move from 14.10 standard release to a point release of 14.04 LTS?

As a matter of fact this is really a downgrade since 14.04.X is a update from 14.04 which is prior to 14.10. Currently, there is not an official way to do this and the safer way is to re-install the system with the desired version.

So, the recommendation is to back up your data, and restart a fresh installation from scratch, then, recover the data from your back up.

How to upgrade an machine using Ubuntu to most recent version without internet access?

You are able to upgrade your system to the next level even if you don't have internet access, as for example, upgrading from Beta to GA release, or even, upgrading to the next release version, as 14.04 to 14.04.2.

You must remember that the Ubuntu CD doesn't contain every package in the repository, so, you are only going to upgrade the main package for the distro, other packages will not be upgradable if you have installed them. (In this case, I would recommend doing a archive mirror using ubumirror tool).

In order to execute the procedure, it is quite easy, following these steps:

  1. If you don't have internet, go to your repository source list and remove the internet repositories commenting them, as:

    # deb http://ports.ubuntu.com/ubuntu-ports/ utopic-updates main restricted

  2. Grab the ISO image you want to upgrade to, and move it to the machine you want to upgrade
  3. Mount it at /media/cdrom, using the following command:

    # mount -o loop  <.ISO> /media/cdrom (avoid using another directory other than /media/cdrom otherwise you are going to change apt-get options later)

  4. Add the mounted directory to the reposiorty source list (/etc/apt/source.list) using the following command:

    # apt-cdrom  -d=/media/cdrom/  add -m

  5. Double check that /etc/apt/sources.list has a line like the following:

    deb cdrom:[Ubuntu-Server 14.10 _Utopic Unicorn_ - Release ppc64el (20141022.2)]/ utopic main restricted

  6. Here after, just do the standard procedure to install the system, as updating the repository, using:

    # apt-get update

  7. Then upgrade the packages to the newer version, using:

    # apt-get upgrade


Here are some of the outputs when executing those commands:

  • sudo mount utopic-server-ppc64el_2014-10-29.iso  /media/cdrom/
    
    mount: /dev/loop0 is write-protected, mounting read-only
    
    
    
    sudo apt-cdrom  -d=/media/cdrom/  add -m
    
    Using CD-ROM mount point /media/cdrom/
    
    Identifying... [a726897a34d7d7434e324566e03954de-2]
    
    Scanning disc for index files...
    
    Found 2 package indexes, 0 source indexes, 0 translation indexes and 1 signatures
    
    This disc is called:
    
    'Ubuntu-Server 14.10 _Utopic Unicorn_ - Release ppc64el (20141022.2)'
    
    Copying package lists...gpgv: Signature made Wed 22 Oct 2014 02:08:40 PM EDT using DSA key ID FBB75451
    
    gpgv: Good signature from "Ubuntu CD Image Automatic Signing Key <cdimage@ubuntu.com>"
    
    Reading Package Indexes... Done
    
    Writing new source list
    
    Source list entries for this disc are:
    
    deb cdrom:[Ubuntu-Server 14.10 _Utopic Unicorn_ - Release ppc64el (20141022.2)]/ utopic main restricted
    
    Repeat this process for the rest of the CDs in your set.
    
    cat /etc/apt/sources.list | grep -v ^# | grep -v  ^$
    
    deb cdrom:[Ubuntu-Server 14.10 _Utopic Unicorn_ - Release ppc64el (20141022.2)]/ utopic main restricted
    
    
    sudo apt-get update
    
    Ign cdrom://Ubuntu-Server 14.10 _Utopic Unicorn_ - Release ppc64el (20141022.2) utopic InRelease
    
    Ign cdrom://Ubuntu-Server 14.10 _Utopic Unicorn_ - Release ppc64el (20141022.2) utopic/main Translation-en_US
    
    Ign cdrom://Ubuntu-Server 14.10 _Utopic Unicorn_ - Release ppc64el (20141022.2) utopic/main Translation-en
    
    Ign cdrom://Ubuntu-Server 14.10 _Utopic Unicorn_ - Release ppc64el (20141022.2) utopic/restricted Translation-en_US
    
    Ign cdrom://Ubuntu-Server 14.10 _Utopic Unicorn_ - Release ppc64el (20141022.2) utopic/restricted Translation-en
    
    Reading package lists... Done
    
    
    sudo apt-get upgrade
    
    Reading package lists... Done
    
    Building dependency tree       
    
    Reading state information... Done
    
    Calculating upgrade... The following packages were automatically installed and are no longer required:
    
      docbook-to-man g++-4.8 libavcodec54 libavformat54 libavutil52 libcamel-1.2-45 libcolord1 libcolorhug1 libept1.4.12 libgail-3-0 libgdata13
    
      libgnome-desktop-3-7 libgnutls28 libgtop2-7 libpoppler44 libqmi-glib0 libqt5positioning5 libqt5sensors5 libqt5test5 libt1-5 libwpd-0.9-9 libwpg-0.2-2
    
      libwps-0.2-2 linux-headers-3.15.0-4 linux-headers-3.15.0-4-generic linux-headers-3.15.0-6 linux-headers-3.15.0-6-generic linux-headers-3.16.0-3
    
      linux-headers-3.16.0-3-generic linux-headers-3.16.0-6 linux-headers-3.16.0-6-generic linux-image-3.15.0-4-generic linux-image-3.15.0-6-generic
    
      linux-image-3.16.0-3-generic linux-image-3.16.0-6-generic linux-image-extra-3.15.0-4-generic linux-image-extra-3.15.0-6-generic
    
      linux-image-extra-3.16.0-3-generic linux-image-extra-3.16.0-6-generic python-cloudfiles python-gnomekeyring python-libxml2 python-pycurl python-smbc
    
      samba-dsdb-modules servicelog
    
    Use 'apt-get autoremove' to remove them.
    
    Done
    
    The following packages have been kept back:
    
      libbz2-1.0 libpng12-0
    
    The following packages will be upgraded:
    
      libpam-modules libpam-modules-bin libpam0g libpciaccess0 libselinux1 libtiff5 linux-firmware linux-headers-3.16.0-23 linux-headers-3.16.0-23-generic
    
      linux-image-3.16.0-23-generic linux-image-extra-3.16.0-23-generic linux-libc-dev plymouth-theme-ubuntu-text
    
    13 upgraded, 0 newly installed, 0 to remove and 2 not upgraded.
    
    Need to get 0 B/85.1 MB of archives.
    
    After this operation, 49.2 kB of additional disk space will be used.
    
    Do you want to continue? [Y/n] y
    
    Preconfiguring packages ...
    
    (Reading database ... 380705 files and directories currently installed.)
    
    Preparing to unpack .../libpam0g_1.1.8-3ubuntu4_ppc64el.deb ...
    
    Unpacking libpam0g:ppc64el (1.1.8-3ubuntu4) over (1.1.8-3ubuntu3) ...
    
    Setting up libpam0g:ppc64el (1.1.8-3ubuntu4) ...
    
    Processing triggers for libc-bin (2.19-10ubuntu2) ...
    
    (Reading database ... 380705 files and directories currently installed.)
    
    Preparing to unpack .../libselinux1_2.3-1build1_ppc64el.deb ...
    
    Unpacking libselinux1:ppc64el (2.3-1build1) over (2.3-1) ...
    
    Setting up libselinux1:ppc64el (2.3-1build1) ...

Virtualization

What is the difference between the PowerKVM and using Ubuntu as hypervisor

There is a set of differences, mainly some features that were not made upstream yet, as:

  • Huge DDW for the guests
    • Status: Some folks working to enable Huge DDW exploitation in Linux kernel and Qemu

Kernel

I want to use the most recent kernel on my Ubuntu

Canonical has a https://launchpad.net/~canonical-kernel-team/+archive/ubuntu/ppa that contains the most upstream kernel available for you to test. It might not be well tested, neither ready for production ready, but, it might help you to do some tests with a recent kernel.

In order to use it, you should add the PPA repository to your source list file, as:

   deb http://ppa.launchpad.net/canonical-kernel-team/ppa/ubuntu YOUR_UBUNTU_VERSION_HERE main 
   deb-src http://ppa.launchpad.net/canonical-kernel-team/ppa/ubuntu YOUR_UBUNTU_VERSION_HERE main  

Later, just install the most upstream release of your kernel.

For example, in order to install kernel 3.19 in vivid, I just did the following:

# cat <<EOF >> /etc/sources.list
deb http://ppa.launchpad.net/canonical-kernel-team/ppa/ubuntu vivid main
deb-src http://ppa.launchpad.net/canonical-kernel-team/ppa/ubuntu vivid main
EOF 

# apt-get install linux-image-3.19.0-6-generic

# reboot
.....

# uname -a
Linux ubuntu1504 3.19.0-6-generic #6-Ubuntu SMP Mon Feb 23 10:49:25 UTC 2015 ppc64le ppc64le ppc64le GNU/Linux

ppc64el/CommonQuestions (last edited 2018-05-10 13:47:29 by breno-leitao)