all posts tagged redhat


by on September 22, 2015

Docker Global Hack Day #3, Bangalore Edition

We organized Docker Global Hack Day at Red Hat Office on 19th Sep’15. Though there were lots RSVPs, the turn up for the event was less than expected. We started the day by showing the recording of kick-off event.

Docker Global Hack #3The teams here worked on four different ideas, out of which two submitted to the Global Hack github page. The four ideas on which teams worked on are:-

Alan and Fayiz worked on PaaS idea, which can be used for setting up dev and qa environment.

Archit was winner of Docker Global Hack Day #2 as well for the same project. He updated the same project in this hackathon. His project is about crowd source analysis by using distributed computing  through  Docker.

  • Visualizing Docker Networking – Himanshu Roy

Himanshu was exploring the idea of visualizing multi-host Docker networking.

  • Spreading and collating containers on GlusterFS with runC -Mohamed Ashiq Liyazudeen, Hari Gowtham

By looking at runC demo in the kick-off video, we thought it would be good if we can run containers on GlusterFS and use it move containers around by saving and restoring the containers on shared volume.

I did not work on specific idea but I was helping teams and other attendees with their questions. I also worked on my upcoming tutorial at Linux Con, Europe on Data and Networking management with containers.

May be because of long weekend and other events we got less participation. Hopefully we do better next time.

by on February 16, 2014

Running GlusterFS inside docker container

As a part of GlusterFS 3.5 testing and hackathon, I decided to put GlusterFS inside a docker container.So I installed docker on my Fedora20 desktop

$ yum install docker-io -y
$ systemctl enable docker.service
ln -s '/usr/lib/systemd/system/docker.service' '/etc/systemd/system/multi-user.target.wants/docker.service'
$ systemctl start docker.service
$ docker version
Client version: 0.7.6
..
Server version: 0.7.6

and then started a Fedora container

$ docker run -i -t mattdm/fedora /bin/bash

Once I am inside the container I installed GlusterFS packages

bash-4.2# yum install glusterfs glusterfs-server -y

And then tried to create volume

bash-4.2# /usr/sbin/glusterd
bash-4.2# gluster volume create vol 172.17.0.3:/mnt/brick/ force


but I got following error:-

volume create: vol: failed: Glusterfs is not supported on brick: 172.17.0.3:/mnt/brick.
Setting extended attributes failed, reason: Operation not permitted.

From above error it looked as setting up extended attributes are not supported, which is a basic need to use GlusteFS. So I tried to test them manually. I was able to set extended attributes in user namespace but not in trusted namespace.

bash-4.2# yum install attr -y
bash-4.2# setfattr -n user.foo1 -v "bar" a
bash-4.2# touch a; setfattr -n trusted.foo1 -v "bar" a
setfattr: a: Operation not permitted

With some internet search I figured out that CAP_SYS_ADMIN is needed for setting up extended attributes in trusted namespace and to get that inside docker we need to run an image with –privileged=true option like

$ docker run --privileged=true -i -t mattdm/fedora /bin/bash

With that I was able to create the volume and start it

bash-4.2# gluster volume create vol 172.17.0.3:/mnt/brick/ force
bash-4.2# gluster volume start vol

But when I tried to mount the volume I got following error:-

E [mount.c:267:gf_fuse_mount] 0-glusterfs-fuse: cannot open /dev/fuse (No such file or directory)

this turned out to be image specific problem, which I am using (mattdm/fedora). I had to mknod for /dev/fuse

bash-4.2# mknod /dev/fuse c 10 229

and after that I was able to mount volume.

On Fedroa 20 for docker version 0.7.6 the default storage driver for docker is device-mapper on which extended attributes are supported. AUFS storage driver does not support extended attributes as of now.I have tried with btrfs storage driver with docker 0.8 as well and was able to use GlusterFS. To use btrfs storage driver, we need to start docker daemon with following command :-

$ docker -d -s btrfs

Above will only work if Docker is running on a btrfs partition already prepared by the host system.

by on September 16, 2013

GlusterFS presentation @LSPE-IN, Yahoo!

Last  Saturday on 14th September’13 I gave on GlusterFS presentation at LSPE-IN. The title for the presentation was Performance Characterization in Large distributed file system with GlusterFS . Few days before the talk I looked at the attendee list to get  the feel of the audience. I felt  that not many of them have used GlusterFS by now. So I decided rather than covering lots of performance part I should cover the concepts of GlusterFS and talk about the performance challenges which can be there by design like file-system in user-space etc.

I am glad I did that as there were only 4 folks from ~70 attendees who have used GlusterFS before.

By going through the concepts the audience were able to compare GlusterFS with other solutions in the market. They asked interesting question about hashing algorithm, replication etc.

IMG_0649_v1

I attended the meetup till lunch. Other than giving the presentation I attended a keynote on Challenges in scaling cloud storage  by Srivibhavan (Vibhav) Balaram in which he talked about the challenges in cloud storage and  QoS in cloud environment. I also attended “Scaling using event driven programming with Perl, A tutorial”  Aveek Mishra.

This was again a very informative and well managed event. I’ll look forward to attend and present in future meet-ups.

by on September 2, 2013

Puppet-Gluster and me at Linuxcon

John Mark Walker, (from Redhat) has been kind enough to invite me to speak at the Linuxcon Gluster Workshop in New Orleans. I’ll be speaking about puppet-gluster, giving demos, and hopefully showing off some new features. I’m also looking forward to meeting up with gluster expert Joe Julian.

If there are features that puppet-gluster is missing, or you have a use case that I haven’t covered, please let me know, and I’ll try to work on it for you ahead of the conference. If you want to meet up for some puppet-gluster help, or to hack on code, I’ll be around from the 16th to the 20th of September. My talk is on the 19th.

Special thanks to John Mark and Redhat for sponsoring this trip. Without them, none of this would be possible.

Happy hacking,

James