User talk:Jch

About NFS

NFS is now working with AL. Both as server and client with the nfs-utils package.
However, to use NFS as client in some LXC does not seems to work yet as shown below

nfstest:~# mount -t nfs -o ro 192.168.1.149:/srv/boot/alpine /mnt
mount.nfs: Operation not permitted
mount: permission denied (are you root?)
nfstest:~# tail /var/log/messages 
Apr  4 10:05:59 nfstest daemon.notice rpc.statd[431]: Version 1.3.1 starting
Apr  4 10:05:59 nfstest daemon.warn rpc.statd[431]: Flags: TI-RPC 
Apr  4 10:05:59 nfstest daemon.warn rpc.statd[431]: Failed to read /var/lib/nfs/state: Address in use
Apr  4 10:05:59 nfstest daemon.notice rpc.statd[431]: Initializing NSM state
Apr  4 10:05:59 nfstest daemon.warn rpc.statd[431]: Failed to write NSM state number: Operation not permitted
Apr  4 10:05:59 nfstest daemon.warn rpc.statd[431]: Running as root.  chown /var/lib/nfs to choose different user
nfstest:~# ls -l /var/lib/nfs
total 12
-rw-r--r--    1 root     root             0 Nov 10 15:43 etab
-rw-r--r--    1 root     root             0 Nov 10 15:43 rmtab
drwx------    2 nobody   root          4096 Apr  4 10:05 sm
drwx------    2 nobody   root          4096 Apr  4 10:05 sm.bak
-rw-r--r--    1 root     root             4 Apr  4 10:05 state
-rw-r--r--    1 root     root             0 Nov 10 15:43 xtab

msg from ncopa """ dmesg should tell you that grsecurity tries to prevent you to do this.

grsecurity does not permit the syscall mount from within a chroot since that is a way to break out of a chroot. This affects lxc containers too.

I would recommend that you do the mouting from the lxc host in the container config with lxc.mount.entry or similar.

https://linuxcontainers.org/lxc/manpages/man5/lxc.container.conf.5.html#lbAR

If you still want disable mount protection in grsecurity then you can do that with: echo 0 > /proc/sys/kernel/grsecurity/chroot_deny_mount """

this is not working with

lxc.mount.entry=nfsserver:/srv/boot/alpine mnt nfs nosuid,intr 0 0

on the host machine with all nfs modules and helper software installed and loaded.

backend:~# lxc-start -n nfstest
lxc-start: conf.c: mount_entry: 2049 Invalid argument - failed to mount
'nfsserver:/srv/boot/alpine' on '/usr/lib/lxc/rootfs/mnt'
lxc-start: conf.c: lxc_setup: 4163 failed to setup the mount entries for
'nfstest'
lxc-start: start.c: do_start: 688 failed to setup the container
lxc-start: sync.c: __sync_wait: 51 invalid sequence number 1. expected 2
lxc-start: start.c: __lxc_start: 1080 failed to spawn 'nfstest'

Nor with

echo 0 > /proc/sys/kernel/grsecurity/chroot_deny_mount

on the host machine with all nfs modules and helper software installed and loaded which does'nt work either.

To find a proper way to use NFS shares from AL LXC is an important topic in order to be able to, for instance, load balance web servers sharing contents uploaded by users.

Next step will be to have HA for the NFS server itself (with only AL machines).

About NBD

NBD is now in edge/testing thanks to clandmeter.

I cannot test it properly at the moment because all the machine are busy in prod. and this package allows newstyle only. I'm waiting my new lab machine...

We still miss xnbd fot it's proxy features allowing live migration. We are very exited by xnbd capacities!
Will be avid tester!

Also we are still looking after the right solution to backup NBD as a whole (versus by it's content) while in use. dd|nc is the used way nowadays.

About consul

nothing yet but big hopes ^^
I'm lurking IRC about it ;)

We plan to use it's dynamic DNS feature, it's hosts listing, services inventory, events, k/v store...
and even semi high-availability for our PXE infrastructure the consul leader being the active PXEserver and other consul server are dormant PXEservers.
All config scripts adapted to pull values out of consul k/v datastore based on profiles found out of consul various lists.
As the key for dhcpd and PXEboot is the hwaddr, it will become our uuid for LAN and consul too.
We are very exited by consul capacities!
Will be avid tester!

Open questions:

1. What memory footprint is needed?
2. What about dynamycally adapt quorum size?
3. Are checks possible triggers?

   • consul watch -prefix type -name name /path/to/executable

   • consul event [options] -name name [payload]

4. What best practice to store etc configurations?
   • http://code.hootsuite.com/distributed-configuration-management-and-dark-launching-using-consul/
   • http://agiletesting.blogspot.fr/2014/11/service-discovery-with-consul-and.html
   • envconsul
   • consul-template

Lab environment:

Je vais préparer 5 KVM pour faire des tests entre-eux. Elles seront reliées à l'OVS "vpn" à la place de "lan" de façon à ne pas perturber la prod.

3 seront des PXEserver et des consul server. Ils n'ont pas besoin de HDD. 1 sera consul leader et dhcpd actif.

2 seront des PXEclient et des consul agent. Ceux-ci ont un HDD monté en mode data (/var pour héberger d'éventuels LXC ou directement des services).

Le seul accès possible à ces 5 machines sera par leur console dans le screen sur le socle concerné.

C'est l'occasion de tester la procédure de bootstrap d'un cluster. En bootant une KVM depuis un stick USB virtuel dont eth0 est connecté à l'OVS "vpn". Configurant cette KVM pour être PXE server. Lancer une seconde KVM par PXEboot, la configurer comme un SAN sur base d'un NBD passé comme /dev/vda plutôt que /dev/md0 et y installer un repo de alpine/stable/x86_64. Lancer une troisième KVM par PXEboot et y installer un environnement PXEserver et consul server en run-from-ram. Rebooter. Basculer le dhcpd actif depuis la KVM-stick vers la KVM-pxe. Éteindre la KVM-stick. À ce stade nous disposons d'un PXEserver actif, consul leader de surcroît; d'un SAN temporaire (à moins que son LVM2 soit basé (in fine) sur un vrai storage). Lançons par PXEboot 2 PXEserver supplémentaires dont les serveurs dhcpd sont désactivés. Joignons les au quorum consul. La première KVM-pxe (consul leader à ce stade) se retire du cluster consul et reboot. Un nouveau consul leader est élu. Il active son serveur dhcpd. La KVM-pxe rejoint le quorum consul et reconnaît le nouveau leader. Elle n'active donc pas son serveur dhcpd. 2 KVM supplémentaires sont instanciées avec un NBD comme /dev/vda. Ces KVM se configurent en mode data (/var). S'enregistrent auprès de consul et auprès du serveur PXE actif (le consul leader) puis reboot (sur leur configuration spécifique donc).

Là nous disposerons d'une infrastructure suffisante pour pouvoir évaluer consul pour notre cas d'usage.

log of experimentation at User_talk:Jch/consul

About CEPH

CEPH is supposed to sovle the problem of high availability for the data stores, be it block devices (disks) or character devices (files).

The actual situation is not satisfactory.

We are very exited by CEPH capacities!
Will be avid tester!

About Docker

not a lot of information on the Docker page yet ...