Abe's questions

Here's the output I get when I run mpstat:

$mpstat
Linux 3.2.0-30-generic (my-laptop-C650)     09/17/2012  _x86_64_    (2 CPU)

05:32:01 PM  CPU    %usr   %nice    %sys %iowait    %irq   %soft  %steal  %guest   %idle
05:32:01 PM  all    9.16    0.08    2.69    2.00    0.00    0.04    0.00    0.00   86.02

And here's what I get when I run it with a one-second interval:

$mpstat 1
05:31:51 PM  CPU    %usr   %nice    %sys %iowait    %irq   %soft  %steal  %guest   %idle
05:31:52 PM  all    1.52    0.00    1.01    0.00    0.00    0.00    0.00    0.00   97.47
05:31:53 PM  all    2.04    0.00    1.02    0.00    0.00    0.00    0.00    0.00   96.94
05:31:54 PM  all    1.50    0.00    1.50    0.00    0.00    0.00    0.00    0.00   97.00

Why does the first process show the processor as 86% idle, and the second show it as ~97% idle? I've tried this in a bunch of different configurations, and it's not a real difference in CPU usage -- unless mpstat itself is making the difference.

Which number should I trust?

I'm writing a hadoop configuration script, but I'm running into trouble installing ganglia. The script needs to run all the way through without any human intervention. Unfortunately, but when it hits this line, it breaks:

sudo apt-get install ganglia-monitor ganglia-webfrontend

The script freezes here. If you attempt to break out with Ctrl-D, or Ctrl-C it fails badly after attempting to run a bunch of commands

Looking more closely, the problem is that ganglia demands user input when you install it. During the apt-get call, a screen like this pops up:

Package configuration

------------------[ Configuring ganglia-webfrontend ]------------------

In order to activate the new configuration, the web server needs to be restarted.
If you choose not to do this automatically, you should do so manually at the first opportunity.                                                                                                              

Restart apache2?
<No>  <Yes>

Is there any way to avoid this screen? Adding the -y tag to apt-get (i.e. apt-get install ganlgi -y) doesn't work.

I'm running django/celery on EC2, with rabbitmq as the broker. The machine I was using failed, so I fired up another instance. But since switching to the new machine, I haven't been able to get celery to work.

EDIT: I've included a lot of logs below, just in case I'm misdiagnosing the problem. But I'm 85% sure that the problem is that rabbitmq-server fails to start up in the "starting database" phase.

node          : rabbit@ip-10-212-66-181
app descriptor: /usr/lib/rabbitmq/lib/rabbitmq_server-1.7.2/sbin/../ebin/rabbit.app
home dir      : /var/lib/rabbitmq
cookie hash   : 5+uQ077En5bpvle3HJCQMg==
log           : /var/log/rabbitmq/rabbit.log
sasl log      : /var/log/rabbitmq/rabbit-sasl.log
database dir  : /var/lib/rabbitmq/mnesia/rabbit

starting internal event notification system                           ...done
starting logging server                                               ...done
starting database                                                     ...Erlang has closed

Any ideas on how to further diagnose/solve this problem?

Here's what happens when I try to run celery:

$ python manage.py celeryd -l info
/opt/bitnami/python/lib/python2.6/site-packages/django_celery-2.4.2-py2.6.egg/djcelery/loaders.py:86: UserWarning: Using settings.DEBUG leads to a memory leak, never use this setting in production environments!
  warnings.warn("Using settings.DEBUG leads to a memory leak, never "
[2011-12-05 19:40:13,545: WARNING/MainProcess]  

 -------------- celery@ip-10-212-66-181 v2.4.3
---- **** -----
--- * ***  * -- [Configuration]
-- * - **** ---   . broker:      amqp://guest@localhost:5672//
- ** ----------   . loader:      djcelery.loaders.DjangoLoader
- ** ----------   . logfile:     [stderr]@INFO
- ** ----------   . concurrency: 1
- ** ----------   . events:      OFF
- *** --- * ---   . beat:        OFF
-- ******* ----
--- ***** ----- [Queues]
 --------------   . celery:      exchange:celery (direct) binding:celery


[Tasks]
  . tbAnalytics.models.processAnalysis
  . tbCollections.models.processCollection

[2011-12-05 19:40:13,558: INFO/PoolWorker-1] child process calling self.run()
[2011-12-05 19:40:13,562: WARNING/MainProcess] celery@ip-10-212-66-181 has started.
[2011-12-05 19:40:13,564: ERROR/MainProcess] Consumer: Connection Error: [Errno 111] Connection refused. Trying again in 2 seconds...
[2011-12-05 19:40:15,574: ERROR/MainProcess] Consumer: Connection Error: [Errno 111] Connection refused. Trying again in 4 seconds...

Tracing it back, it looks like the rabbitmq server is the problem, and the database in particular:

$ sudo rabbitmqctl status
Status of node 'rabbit@ip-10-212-66-181' ...
Error: unable to connect to node 'rabbit@ip-10-212-66-181': nodedown
diagnostics:
- nodes and their ports on ip-10-212-66-181: [{rabbitmqctl14448,38289}]
- current node: 'rabbitmqctl14448@ip-10-212-66-181'
- current node home dir: /var/lib/rabbitmq
- current node cookie hash: 5+uQ077En5bpvle3HJCQMg==

But I haven't been able to figure out how to restart the server:

bitnami@ip-10-212-66-181:/var/log/rabbitmq$ sudo rabbitmq-server start_app

+---+   +---+
|   |   |   |
|   |   |   |
|   |   |   |
|   +---+   +-------+
|                   |
| RabbitMQ  +---+   |
|           |   |   |
|   v1.7.2  +---+   |
|                   |
+-------------------+
AMQP 8-0
Copyright (C) 2007-2010 LShift Ltd., Cohesive Financial Technologies LLC., and Rabbit Technologies Ltd.
Licensed under the MPL.  See http://www.rabbitmq.com/

node          : rabbit@ip-10-212-66-181
app descriptor: /usr/lib/rabbitmq/lib/rabbitmq_server-1.7.2/sbin/../ebin/rabbit.app
home dir      : /var/lib/rabbitmq
cookie hash   : 5+uQ077En5bpvle3HJCQMg==
log           : /var/log/rabbitmq/rabbit.log
sasl log      : /var/log/rabbitmq/rabbit-sasl.log
database dir  : /var/lib/rabbitmq/mnesia/rabbit

starting internal event notification system                           ...done
starting logging server                                               ...done
starting database                                                     ...Erlang has closed
{"init terminating in do_boot",{{nocatch,{error,{cannot_start_application,rabbit,{bad_return,{{rabbit,start,[normal,[]]},{'EXIT',{{case_clause,{error,{timeout_waiting_for_tables,[rabbit_user,rabbit_user_permission,rabbit_vhost,rabbit_config,rabbit_listener,rabbit_durable_route,rabbit_route,rabbit_reverse_route,rabbit_durable_exchange,rabbit_exchange,rabbit_durable_queue,rabbit_queue]}}},[{rabbit,'-run_boot_step/1-lc$^1/1-1-',1},{rabbit,run_boot_step,1},{rabbit,'-start/2-lc$^0/1-0-',1},{rabbit,start,2},{application_master,start_it_old,4}]}}}}}}},[{init,start_it,1},{init,start_em,1}]}}

Crash dump was written to: erl_crash.dump
init terminating in do_boot ()

Also, don't know if it's relevant, but this process is running in the background.

$ ps aux | grep rabbit
rabbitmq   714  0.0  0.0   1980   408 ?        S    Dec04   0:00 /usr/lib/erlang/erts-5.7.4/bin/epmd -daemon

I haven't been able to find any documentation for this kind of failure. Any suggestions?

I'm trying to install gedit on an Amazon EC2 instance running Redhat 4.4.4-13. I thought it would be as easy as

sudo yum install gedit

But that just gives me:

Loaded plugins: fastestmirror, priorities, security
Loading mirror speeds from cached hostfile
amzn-main                                                | 2.1 kB     00:00     
amzn-updates                                             | 2.1 kB     00:00     
Setting up Install Process
No package gedit available.
Error: Nothing to do

Trying "yum repolist all" gives me this:

repo id                          repo name                        status
amzn-main                        amzn-main-Base                   enabled: 2,463
amzn-main-debuginfo              amzn-main-debuginfo              disabled
amzn-main-nosrc                  amzn-main-nosrc                  disabled
amzn-updates                     amzn-updates-Base                enabled:    86
amzn-updates-debuginfo           amzn-updates-debuginfo           disabled
amzn-updates-nosrc               amzn-updates-nosrc               disabled
repolist: 2,549

So it looks as though this machine doesn't have any of the usual repositories, including those with gedit. How do I install those? I can't find any documentation on this.