Dumping memcached

I needed to see if memcached was getting the values I thought it was getting. Everyone knows about "stats" to see if it is getting activity, but I looked around and found that it is possible to get some of that data out without knowing how your app stores the data. So I wrote a script to do it:

#!/bin/sh
HOST="localhost"
if [ "$1" != "" ]; then HOST=$1; fi
COUNT=100
if [ "$2" != "" ]; then COUNT=$2; fi
for slab in `echo "stats items" | nc $HOST 11211 | grep :number | cut -d: -f2 -`
do
  for item in `echo "stats cachedump $slab $COUNT" | nc $HOST 11211 | grep "^ITEM" | cut -d" " -f2 -`
  do
    echo "get $item" | nc $HOST 11211
  done
done

On Cloud n+1

I spent the last few days setting up an autoscaling pool of servers on the Amazon Elastic Compute Cloud. They really have done an excellent job of putting together a great toolset and documentation. I've made some notes on how to do a basic setup, including using the EC2 Elastic Load Balancer. Another cool tool I was able to use for this project was Ubuntu's pre-built EC2 images and the cloud-init package, making auto-deployment of the servers very easy to do.

# Notes on setting up Amazon AWS Auto Scaling
# ===========================================
# ATonns Tue Oct 26 17:37:12 EDT 2010
#

export AVAILZONE="us-east-1a"
#
# create a launch config
#
export LCNAME="test-lc"
as-create-launch-config $LCNAME \
 --image-id ami-f5e0049c \
 --instance-type m1.small
#
# other key args:
#
# /* security group */
# --group {groupname}
# /* meta-data file */
# --user-data-file {filename}
#

#
# create a load balancer
#
export LBNAME="test-lb"
elb-create-lb $LBNAME --headers \
 --availability-zones $AVAILZONE \
 --listener "protocol=http,lb-port=80,instance-port=80" 
#
# add some thresholds that will kick instances out
#
export LBTESTURI="/DONOTREMOVE.php"
elb-configure-healthcheck $LBNAME --headers \
 --target "HTTP:80$LBTESTURI" \
 --interval 5 \
 --timeout 2 \
 --unhealthy-threshold 2 \
 --healthy-threshold 5

#
# create auto-scale group
#
export ASGROUP="test-asg"
as-create-auto-scaling-group $ASGROUP \
 --availability-zones $AVAILZONE \
 --launch-configuration $LCNAME \
 --min-size 1 \
 --max-size 5 \
 --load-balancers $LBNAME

#
# create a trigger
#
export ASTRIGGER="test-trig"
as-create-or-update-trigger $ASTRIGGER \
 --auto-scaling-group $ASGROUP \
 --period 60 \
 --unit Seconds \
 --dimensions "LoadBalancerName=$LBNAME" \
 --namespace "AWS/ELB" \
 --measure Latency \
 --statistic Average \
 --lower-threshold 0.25 \
 --upper-threshold 0.75 \
 --breach-duration 300 \
 --lower-breach-increment=-1 \
 --upper-breach-increment 1 

#
# more metrics
#
http://goo.gl/A4pAd

------------

#
# remove everything
#
as-delete-trigger $ASTRIGGER --auto-scaling-group $ASGROUP --force
as-update-auto-scaling-group $ASGROUP --min-size 0 --max-size 0
count="-1"
while [ $count -ne 0 ]
do
 count=0
 for i in `as-describe-auto-scaling-groups $ASGROUP --show-long`
 do
  type=`echo $i | cut -d, -f1 -`
  if [ $type = INSTANCE ]
  then
   count=`expr $count + 1`
  fi
 done
 echo $count instances left
done
procs="-1"
while [ $procs -ne 0 ]
do
 procs=0
 for i in `as-describe-scaling-activities $ASGROUP --show-long | cut -d, -f4 -`
 do
  if [ "$i" != "Successful" ]
  then
   procs=`expr $procs + 1`
  fi
 done
 echo $procs processes still running
done
as-delete-auto-scaling-group $ASGROUP --force
as-delete-launch-config $LCNAME --force
elb-delete-lb $LBNAME --force