Omry's questions

I'm new to SNMP.

Installed an SNMP server (net-snmp 5.4.3 on Debian), and I`m trying to go through this tutorial : http://oreilly.com/perl/excerpts/system-admin-with-perl/twenty-minute-snmp-tutorial.html

I am getting a strange response for the following query:

# snmpgetnext -v 1 -c public localhost  \
    ip.ipRouteTable.ipRouteEntry.ipRouteDest \
    ip.ipRouteTable.ipRouteEntry.ipRouteNextHop

HOST-RESOURCES-MIB::hrSystemUptime.0 = Timeticks: (67626825) 7 days, 19:51:08.25
HOST-RESOURCES-MIB::hrSystemUptime.0 = Timeticks: (67626825) 7 days, 19:51:08.25

I would expect to get some routing table information, but instead I get the system uptime (twice).

any idea why?

I am trying to build a new image based on "debian-6.0-squeeze-64bit-minimal-pvgrub-20110222-05 (ami-1e39ca77)", and it seems to be missing the ephemeral disks:

fdisk -l shows only /dev/xvda1 (ebs root device), and the block device mapping does not show the local disks.

GET http://169.254.169.254/latest/meta-data/block-device-mapping/
ami

the instance type is m1.xlarge which comes with 4 local disks:

echo  $(GET http://169.254.169.254/latest/meta-data/instance-type)
m1.xlarge

any idea?

I am trying to get an alert from monit if it fails to restart a service 5 times, but I get a syntax error

/etc/monit/monit.d/engine.conf:5: Error: syntax error 'alert'

any idea what's wrong with it?

/etc/monit/monitrc:

set daemon  120
set mailserver localhost

set eventqueue
    basedir /var/monit  # set the base directory where events will be stored
    slots 100           # optionaly limit the queue size


set httpd port 2812
  allow localhost

set logfile syslog

set alert root@localhost

include /etc/monit/monit.d/*

/etc/monit/monit.d/engine.conf (The only file in monit.d) :

check process engine with pidfile /var/run/engine.pid
   group engine
   start program = "/etc/init.d/engine start"
   stop  program = "/etc/init.d/engine stop"
   if 5 restarts within 5 cycles then alert

version:

# monit -V
This is monit version 4.10.1

I am trying to use /etc/security/limit.conf on Linux (Debian) to limit the number of processes per user.

for starters, I tried to limit my own user processes by adding this to /etc/security/limit.conf:

omry hard nproc 100

this locked my user out of ssh. I could open new processes (verified with su omry), but could not log into ssh with that user : sshd reported this in it's log:

fatal: setreuid 1000: Resource temporarily unavailable

also, I am certain my user is not running anything near 100 processes (actually 6). what can be the reason for this?

I am trying to ntp sync one machine with another. both runs Debian lenny, and I installed the ntp package in both. I configured the server to synchronize with an external machine by putting

server IP.ADDRESS iburst

in it's /etc/ntp.conf file.

I configured the client to sync with the serve by putting only the server in /etc/ntp.conf of the client.

however, they do not seem to be synchronizing. ntpq shows that the state is INIT which - according to the docs - indicates that "The association has not yet synchronized for the first time"

# ntpq -n
ntpq> pe
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
 10.99.84.134    .INIT.          16 u  665 1024    0    0.000    0.000   0.000

ntpq -> as shows 'reject' in the condition line:

# ntpq
ntpq> as

ind assID status  conf reach auth condition  last_event cnt
===========================================================
  1 40102  8000   yes   yes  none    reject

Any idea how to solve this? (I would rather not use ntpdate).

I have a master-master setup which I want to move to a new pair of servers (from linux to opensolaris). linux boxes names are shard1-1 and shard1-2, and osol boxes names are shard1-1-osol and shard1-2-osol.

this is what I did: 1. took down mysql server on both linux boxes, copied the data to the osol boxes. 2. edited master.info on each of the osol boxes, changed master from shard1-1 to shard1-1-osol and vice versa on both machines.

when I started mysql on the first osol machine, I see this in the error log: looks like mysql does not like the host name change, and it's bitching about it. the mysqld-relay-bin.000707 file exists in the datadir, so it's not clear what mysql is whining about.

090902  2:26:03  InnoDB: Started; log sequence number 246 3528553673
090902  2:26:03 [Warning] Neither --relay-log nor --relay-log-index were used; so replication may break when this MySQL server acts as a slave and has his hostname changed!! Please use '--relay-log=shard1-1-osol-relay-bin' to avoid this problem.
090902  2:26:03 [ERROR] Failed to open the relay log './mysqld-relay-bin.000707' (relay_log_pos 19653396)
090902  2:26:03 [ERROR] Could not find target log during relay log initialization
090902  2:26:03 [ERROR] Failed to initialize the master info structure

1. I am experiencing a problem where the server runs out of memory in specific scenarios. one solution I am thinking about is to limit the number of clients served concurrently, but have the extra clients wait for a free slot instead of having them get a "too many connections error". is this possible?

2. how do I calculate maximum memory usage per open mysql connection?