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Ludka Furtkevicova edited this page Sep 29, 2015 · 33 revisions

GIS.lab cluster is managed by decentralized cluster management tool called Serf, which is based on gossip protocol. Serf is responsible for automatic joining and removing machines to and from GIS.lab cluster and OWS load balancer management. It is also used as interface for running cluster events and queries.

Roles, events and queries

Machines belonging to GIS.lab cluster are divided into two roles:

  • server: GIS.lab server
  • client: GIS.lab clients

All machines are capable of running different set of cluster events and queries depending on their role membership. Events and queries can be send from any machine which is a member of GIS.lab cluster using gislab-cluster client (which is currently just symlink to serf binary), or programmatically using RPC mechanism. All machines in cluster will receive all events and queries and will decide to respond or not depending on existence of handler responsible for particular event or query.

The main difference between event and query is that while query is designed to send some query and receive response, the purpose of event is just to announce that something has happen or should happen without receiving any response. Response from query can be returned in two formats: text or JSON.

Public events and queries

Here is a list of publicly available events and queries designed for ordinary usage. This list doesn't contain system events and queries which are used for internal GIS.lab cluster management.

Get list of cluster members, theirs roles membership and list of supported events and queries

$ gislab-cluster members

Get list of cluster members in JSON format

$ gislab-cluster members -format json

{
  "members": [
    {
      "name": "server.gis.lab",
      "addr": "192.168.15.5:7946",
      "port": 7946,
      "tags": {
        "role": "server"
      },
      "status": "alive",
      "protocol": {
        "max": 4,
        "min": 2,
        "version": 4
      }
    },
    {
      "name": "c51",
      "addr": "192.168.15.51:7946",
      "port": 7946,
      "tags": {
        "role": "client"
      },
      "status": "alive",
      "protocol": {
        "max": 4,
        "min": 2,
        "version": 4
      }
    },
    {
      "name": "c50",
      "addr": "192.168.15.50:7946",
      "port": 7946,
      "tags": {
        "role": "client"
      },
      "status": "alive",
      "protocol": {
        "max": 4,
        "min": 2,
        "version": 4
      }
    }
  ]
}

Reboot/shutdown all client machines

$ gislab-cluster event reboot
$ gislab-cluster event shutdown

Reboot/shutdown particular client machines

$ gislab-cluster event reboot "<hostname>,<hostname>,..."
$ gislab-cluster event shutdown "<hostname>,<hostname>,..."

Get list of client machines which are currently running user session

$ gislab-cluster members -tag sesion-active=*.

Running commands on whole cluster with parallel-ssh

Deploy public ssh key to your GIS.lab user to allow passwordless login

$ ssh-copy-id -i ~/.ssh/id_rsa.pub  gislab@<GIS.lab server IP>

Get list of currently running client machines

$ MACHINES="$(gislab-cluster members -tag role=client -status=alive | awk -F " " '{printf "%s ", $1}')"

Install gedit on all client machines

$ parallel-ssh -O StrictHostKeyChecking=no -i -H "$MACHINES" sudo DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends gedit

[1] 23:02:57 [SUCCESS] c51
Reading package lists...
Building dependency tree...
Reading state information...
The following NEW packages will be installed:
  gedit
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 0 B/827 kB of archives.
After this operation, 2,781 kB of additional disk space will be used.
Selecting previously unselected package gedit.
(Reading database ... 134642 files and directories currently installed.)
Unpacking gedit (from .../gedit_3.4.1-0ubuntu1_amd64.deb) ...
Processing triggers for desktop-file-utils ...
Setting up gedit (3.4.1-0ubuntu1) ...
update-alternatives: using /usr/bin/gedit to provide /usr/bin/gnome-text-editor (gnome-text-editor) in auto mode.
Processing triggers for libc-bin ...
ldconfig deferred processing now taking place
[2] 23:02:57 [SUCCESS] c50
Reading package lists...
Building dependency tree...
Reading state information...
The following NEW packages will be installed:
  gedit
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 0 B/827 kB of archives.
After this operation, 2,781 kB of additional disk space will be used.
Selecting previously unselected package gedit.
(Reading database ... 134642 files and directories currently installed.)
Unpacking gedit (from .../gedit_3.4.1-0ubuntu1_amd64.deb) ...
Processing triggers for desktop-file-utils ...
Setting up gedit (3.4.1-0ubuntu1) ...
update-alternatives: using /usr/bin/gedit to provide /usr/bin/gnome-text-editor (gnome-text-editor) in auto mode.
Processing triggers for libc-bin ...
ldconfig deferred processing now taking place

Perform performance test of parallel write to network share

$ parallel-ssh -O StrictHostKeyChecking=no -i -H "$MACHINES" 'dd if=/dev/zero of=/mnt/barrel/file-$(hostname).io bs=1M count=1024'

[1] 09:42:11 [SUCCESS] c54
Stderr: 1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 37.7824 s, 28.4 MB/s
[2] 09:42:11 [SUCCESS] c52
Stderr: 1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 38.1136 s, 28.2 MB/s
[3] 09:42:11 [SUCCESS] c51
Stderr: 1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 38.4403 s, 27.9 MB/s
[4] 09:42:12 [SUCCESS] c53
Stderr: 1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 38.6802 s, 27.8 MB/s

Perform performance test of parallel read from network share

$ parallel-ssh -O StrictHostKeyChecking=no -i -H "$MACHINES" 'dd if=/mnt/barrel/file-$(hostname).io of=/dev/zero bs=1M'

[1] 09:42:45 [SUCCESS] c51
Stderr: 1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 0.207453 s, 5.2 GB/s
[2] 09:42:45 [SUCCESS] c53
Stderr: 1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 0.210259 s, 5.1 GB/s
[3] 09:42:45 [SUCCESS] c52
Stderr: 1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 0.227793 s, 4.7 GB/s
[4] 09:42:45 [SUCCESS] c54
Stderr: 1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 0.207774 s, 5.2 GB/s

Perform CPU performance test

$ parallel-ssh -O StrictHostKeyChecking=no -i -H "$MACHINES" 'dd if=/dev/zero bs=1M count=1024 | md5sum'

[1] 09:39:05 [SUCCESS] c52
cd573cfaace07e7949bc0c46028904ff  -
Stderr: Warning: Permanently added 'c52,192.168.19.52' (ECDSA) to the list of known hosts.
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 2.51008 s, 428 MB/s
[2] 09:39:05 [SUCCESS] c53
cd573cfaace07e7949bc0c46028904ff  -
Stderr: Warning: Permanently added 'c53,192.168.19.53' (ECDSA) to the list of known hosts.
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 2.50255 s, 429 MB/s
[3] 09:39:06 [SUCCESS] c54
cd573cfaace07e7949bc0c46028904ff  -
Stderr: Warning: Permanently added 'c54,192.168.19.54' (ECDSA) to the list of known hosts.
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 2.52551 s, 425 MB/s
[4] 09:39:06 [SUCCESS] c51
cd573cfaace07e7949bc0c46028904ff  -
Stderr: Warning: Permanently added 'c51,192.168.19.51' (ECDSA) to the list of known hosts.
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 2.56706 s, 418 MB/s

Remote desktop management

Connecting to running remote desktop session

HOST=<REMOTE-HOST-NAME> ssh gislab@$HOST "x11vnc -bg -safer -once -nopw -scale 0.9x0.9 -display :0 -allow $(hostname -f)" && vncviewer $HOST
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