Missing legacy ethX interfaces names

If you are a old school sys admin, and wants to keep the default ethX convention for internet names,  you can do it easily on Ubuntu and Debian.

When running Ubuntu and Debian on a virtual machine on top of KVM, you will see that the name is ibmvethX, instead of the ethX. This changes happened on newer version (Ubuntu 15.10+ and Debian 10) due to a lot of benefits of interfaces naming when doing PCI hot plugs and replacement.

So, in order to solve it you have two options, changing the full ifname mechanism as a general change, doing:

Changing ifname in the kernel

Edit your /etc/default/grub. Change the the following line from:

GRUB_CMDLINE_LINUX=""

to

GRUB_CMDLINE_LINUX="net.ifnames=0 biosdevname=0"

And then running:

# update-grub

Other than doing it, youou can also just change one interface, so, you can have more control.

Persistent udev naming

In order to run persistent name, which I personally prefer better, you can create a file name /etc/udev/rules.d, with the following content:

SUBSYSTEM==”net”, ACTION==”add”, ATTR{address}==”4c:45:42:45:01:09″, NAME=”eth0″

This is going to tell udev that a interface with mac ‘4c:45:42:45:01:09‘ should be named eth0. After that, just replace your configurations at /etc/network/interfaces and reboot your system. You should see eth0 instead of ibmveth0 now.

 

Advertisements

Export X from server to local system

Every now and then I have to verify a graphical application running on the remote server. That must be done via graphical output, no way to do it from the command line.

For those scenarios I usually export the X from the remote interface to my local workstation. That can be done simply by issuing:

ssh -X -C -c blowfish <username>@<remote-server>

From the ssh man page:

-X:
     Enables X11 forwarding. (X11 forwarding should be enabled
     with caution. Read the man page);
-C:
    Requests compression of all data;
-c cipher_spec:
    Selects the cipher specification for encrypting the session.
    The supported values are “3des”, “blowfish”, and “des”.

<EDIT>
Using a remote connection to a xenial ppc64el server from a Fedora24, I got the following error:

Unable to negotiate with <server>: no matching cipher found. 
Their offer: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,
aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com

Adding blowfish-cbc (taken from the openssh man page) to the ssh_config files did not “blow it away” though. So to get rid of the error I simply removed the ‘blowfish‘ cipher type, and left the task to the system.
</EDIT>

After getting access you won’t notice any difference, for the result is the same as as regular ssh connection. The difference relies on the behavior when you run a graphical application from the CLI. Here I am running HardInfo in the remote system as an example:

hardInfo_3.png

Graphical interface being exported to a local workstation from a remote Ubuntu ppc64el system.

Please read the ssh man page carefully to get clearer all security considerations and get advantage of the X exporting when running graphical applications.

Have a nice day.

Debconf BoF presentation

At Debconf16, I was the chair of a nice BoF discussion around Power, covering all the three ports (powerpc, ppc64 and ppc64el).

There was some interesting discussion about powerpc and ppc64, and what to expect  in Stretch release. One of the discussions, raised by the release team, is regarding missing  porters. This should be more detailed later in the release team emails.

I also created a PDF to start the discussion, and I would like to share it here. You can find it clicking in the following like: ppc64el_bof.