Sensu at nycdevops Meetup
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Sensu at nycdevops Meetup

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My sensu tutorial from the nycdevops Meetup on November 14, 2013.

My sensu tutorial from the nycdevops Meetup on November 14, 2013.

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Sensu at nycdevops Meetup Sensu at nycdevops Meetup Presentation Transcript

  • SENSE AND SENSU-BILITY Painless Metrics And Monitoring In The Cloud with Sensu Bethany Erskine nycdevops Meetup http://github.com/skymob/sensu-tutorial Thursday, November 14, 13
  • DO YOU LOVE YOUR MONITORING SETUP? Thursday, November 14, 13
  • #MONITORINGLOVE Thursday, November 14, 13 View slide
  • MY STORY + (╯︵╰,) Thursday, November 14, 13 View slide
  • Thursday, November 14, 13
  • Thursday, November 14, 13
  • WHY SENSU ✓Ruby Plugins can be written in any ✓language ✓ ✓community sensu-chef cookbook Thursday, November 14, 13
  • WHY SENSU ✓re-use Nagios checks metrics and checks all collected by ✓one system ✓ ✓easy to scale Graphite integration Thursday, November 14, 13
  • WHY SENSU ✓“Can I do X with Sensu?” probably! Thursday, November 14, 13
  • WHY SENSU Thursday, November 14, 13
  • WHY SENSU? ✓ Sensu source is well-written and easy to parse ✓ Thursday, November 14, 13 https://github.com/sensu
  • WHY SENSU? ✓sensu-community-plugins 80 contributors ✓ ✓over 600 plugins https://github.com/sensu/sensu✓community-plugins Thursday, November 14, 13
  • TODAY at PAPERLESS Two Sensu environments (prod/testing) ~ 250 - 275 instances of sensu-client 4-6 Sensu-server instances 25k Metrics/Hour to Graphite 1 custom dashboard 1 custom CLI Thursday, November 14, 13
  • RESOURCES All of our ✓virtualized.Sensu infrastructure is We typically give a ✓box 1.5GB RAM and sensu-server 4 processors, scaling up RAM for any box running more than one Sensu service on it. 4GB ✓install RAM for a monolithic Sensu (Rabbit, Redis, all Sensu components on one) Thursday, November 14, 13
  • AS WE GREW Growing pains and lessons learned... Thursday, November 14, 13
  • NEEDS MORE SENSU ✓High load on Sensu server Backed-up queues in RabbitMQ ✓ TIP: set up check to monitor the ✓RabbitMQ ready queue size, you'll want an email when the queue grows about 10K and stays there Thursday, November 14, 13
  • HOW TO SCALE ✓Add more sensu-server instances No special configuration needed ✓ checks will be ✓robin fashion todistributed in roundthe sensu-servers Thursday, November 14, 13
  • GRAPHITE PAINS symptoms: backed up queues in ✓RabbitMQ, spotty graphs cluster couldn’t with the ✓large amount of keep upwe were metrics now serving it via AMQP Thursday, November 14, 13
  • GRAPHITE PAINS ✓ Solution: stop collecting metrics every 10 seconds (excessive!) ✓ moved staging metrics to staging Graphite cluster ✓ Moved prod Graphite cluster to SSD Thursday, November 14, 13
  • THE MIGRATION or, How To Quit Nagios in Ten Easy Steps Thursday, November 14, 13
  • STEP 1: NUKE AND PAVE Thursday, November 14, 13
  • STEP 2: PLAN METRICS AND MONITORING SURVEY Thursday, November 14, 13
  • METRICS AND MONITORING SURVEY Thursday, November 14, 13
  • STEP 3: DEFINE GLOBALS ✓CHECKS: must be actionable! ✓METRICS: go nuts HANDLERS: EMAIL for everything ✓initially, added Pagerduty later. Thursday, November 14, 13
  • OUR GLOBALS ✓ CHECKS: disk usage, swap usage, zombie processes, RO filesystems ✓ METRICS: vmstat, disk usage, cpu, memory, interface and disk perf ✓ HANDLERS: Email, Campfire, Pagerduty Thursday, November 14, 13
  • STEP 4: DEFINE SPECIFICS ✓ For each server role, define additional states to be checked and alerted on: ✓Process Checks ✓System Checks ✓Service Checks ✓Service Metrics Thursday, November 14, 13
  • STEP 5: SET UP A PLACE TO TEST ✓ Set up a permanent testing Sensu stack using your CM tool of choice ✓ Thursday, November 14, 13 we used sensu-chef cookbook
  • STEP 6: SET A WORKFLOW ✓ Develop and document a workflow for implementing, testing, deploying and signing off on checks ✓ You’ll get the best coverage if anyone (developers or ops) can easily add checks and metrics to Sensu Thursday, November 14, 13
  • EXAMPLE WORKFLOW add new sensu_check ✓appropriate cookbook definitions to the in Chef deploy ✓Chef new check to staging env using ✓Pull Request with sample graphs or alerts ✓Code Review from colleague ✓Deploy to Prod Thursday, November 14, 13
  • SENSU IN CHEF Thursday, November 14, 13
  • STEP 7: EXECUTE WORKFLOW Starting with the low-hanging ✓(plugins that already existed infruit sensu-community-plugins repository), configure and deploy each check in the worksheet to the testing Sensu server deploy sensu-client to a few select ✓machines Thursday, November 14, 13
  • STEP 8: WATCH THE WATCHER Set up some bare-minimum 3rd ✓party monitoring for the Sensu servers Thursday, November 14, 13
  • Thursday, November 14, 13
  • MONITOR THE MONITOR ✓ Other ideas: have Testing Sensu monitor Prod Sensu ✓ Sensu can collect metrics about itself Thursday, November 14, 13
  • STEP 9: ROLLOUT Deploy your ✓infrastructureProduction server Roll out the client ✓the rest of the yourand checks to prod environments.  Thursday, November 14, 13
  • STEP 10: TUNE ✓ Expect to need to tune ✓and alert occurrences. thresholds Laissez le bon alertes roulent! Thursday, November 14, 13
  • SENSU ARCHITECTURE Thursday, November 14, 13
  • SENSU ARCHITECTURE Thursday, November 14, 13
  • OMNIBUS INSTALLER is awesome Thursday, November 14, 13
  • LET’S PLAY WITH SENSU If you haven’t been able to get your sandboxes up and running, please pair with someone near you. Thursday, November 14, 13
  • SANDBOX GOALS ✓ Get familiar with Sensu configuration ✓ ✓Deploy a check Trigger an alert on that check ✓ Give you something to take home ✓and hack on Install a Handler Thursday, November 14, 13
  • OOPS If you mess anything up: vagrant halt; vagrant up Worst case: vagrant destroy; vagrant up Thursday, November 14, 13
  • TWO VIRTUALBOXES Sensu-Server and Sensu-Client Vagrant/Chef Centos 6.4 Sensu Version 0.10.2 Thursday, November 14, 13
  • SENSU CONFIGURATION Please open up a terminal ✓into both your sensu-serverand SSH and sensu-client VMs ✓sudo su ✓cd /etc/sensu Thursday, November 14, 13
  • SENSU CONFIGURATION ✓/etc/sensu/config.json - config for redis, rabbitmq, api and dashboard ✓/etc/sensu/conf.d/ - checks go here ✓/etc/sensu/conf.d/client.json client configuration, subscriptions ✓ /etc/sensu/{extensions|handlers| mutators|plugins} Thursday, November 14, 13
  • TRIGGER AN ALERT! On sensu-client: service sensu-client stop Thursday, November 14, 13
  • CHECK YOUR DASHBOARD Open a web browser and ✓http://10.254.254.10:8080 go to username: ✓secret admin / password: Thursday, November 14, 13
  • HANDLERS ✓ A HANDLER takes action on an event using a pipe, TCP, UDP, AMQP, or a set of other handlers Examples: send an send ✓event to Pagerduty,email,metrics to send Graphite ✓ Thursday, November 14, 13 Default is “debug”
  • HANDLER EXAMPLES ✓BASIC: send an email to ops@ ADVANCED: attempt to remediate ✓the alert (i.e. run a custom script that spins up additional ec2 instances) Thursday, November 14, 13
  • HANDLERS Let’s configure an EMAIL handler ✓to send a informative email for an event. ✓ /etc/sensu/handlers/mailer.rb plugin is installed for you, we just need to configure and install it Thursday, November 14, 13
  • CONFIGURE THE PLUGIN ON SENSU SERVER: vim /etc/sensu/conf.d/handlers/ mailer.json { "mailer": { "mail_from": "sensu@you.com", "mail_to": "you@yourdomain.com" } } Thursday, November 14, 13
  • CONFIGURE THE HANDLER cp /etc/sensu/conf.d/handlers/ default.json /etc/sensu/conf.d/handlers/ email.json vim /etc/sensu/conf.d/handlers/ email.json Thursday, November 14, 13
  • EMAIL.JSON "handlers": { "email": { "type": "pipe", "command": "/etc/sensu/handlers/ mailer.rb" } } Thursday, November 14, 13
  • CHECK GEM DEPENDENCIES /opt/sensu/embedded/bin/gem list | grep mail Thursday, November 14, 13
  • FIX PERMISSIONS chown -R .sensu /etc/sensu/conf.d/ Thursday, November 14, 13
  • RESTART SERVICES service sensu-server restart tail -100 /var/log/sensu/sensu-server.log | grep mail Thursday, November 14, 13
  • CHECKS Sensu-client runs CHECKS that ✓defined and scheduled either are locally (standalone) or on the sensu-server (subscription). A CHECK sends a RESULT as ✓EVENT to a HANDLER - this an applies to anything - service checks, metrics, etc Thursday, November 14, 13
  • CHECK EXECUTION ✓ Either scheduled by the server (subscription) or scheduled by the client (standalone) Today we will configure a ✓subscription-based check on the server that will run on our client Thursday, November 14, 13
  • LETS CONFIGURE A CHECK ✓ Use check-procs.rb to make sure at least one instance of cornbread is running Thursday, November 14, 13
  • DETERMINE OUR CHECK COMMAND On your SENSU CLIENT: /opt/sensu/embedded/bin/ruby /etc/sensu/plugins/check-procs.rb -p cornbread -W1 Thursday, November 14, 13
  • INSTALL OUR CHECK ✓On your SENSU SERVER: vim /etc/sensu/conf.d/checks/ ✓cornbread_process.json Thursday, November 14, 13
  • CORNBREAD_PRO CESS.JSON Thursday, November 14, 13
  • RESTART SERVICES service sensu-server restart tail -100 /var/log/sensu/sensu-server.log | grep cornbread Thursday, November 14, 13
  • CHECK YOUR DASHBOARD Thursday, November 14, 13
  • CHECK YOUR EMAIL Thursday, November 14, 13
  • SENSU API ✓ ✓HTTP/4567 on SENSU SERVER try: ✓ REST API curl -l http://localhost:4567/events | python -mjson.tool Thursday, November 14, 13
  • SENSU SERVICES ✓Sensu API Sensu Server ✓ ✓Sensu Client Sensu Dashboard ✓ Thursday, November 14, 13
  • EVERYTHING OK? ✓ /etc/init.d/sensu-service {client| server|api|dashboard} {start|stop| status|restart} ✓ps -ef | grep sensu tail -f /var/log/sensu/*.log ✓ ✓curl -l localhost:4567/info Thursday, November 14, 13
  • COOL SENSU TRICKS Thursday, November 14, 13
  • SEND DIRECTLY TO SENSU netcat to: 127.0.0.0:3030 Thursday, November 14, 13
  • AGGREGATE ALERTS ✓ Alert when ✓not OK X% of checks are are Handy for preventing alert floods Thursday, November 14, 13
  • MY SENSU TIPS install the RabbitMQ management ✓web interface and bookmark it (see http://10.254.254.10:15672/#/ ) ✓ lock your plugins’ gem dependency versions Thursday, November 14, 13
  • TIPS TIPS TIPS ✓ have alternate ways to access your Dashboard information ✓ we integrated our command-line developer tools with Sensu API ✓ we also created our own Ops dashboard that queries Sensu, Graphite and our app for data Thursday, November 14, 13
  • MORE TIPS ✓ Put NGINX in front of sensudashboard Thursday, November 14, 13
  • HA SENSU ✓ Redundancy is easy (bring up more sensu-servers) ✓ Making Redis and RabbitMQ HA more challenging ✓ We’re still running one solitary Redis and RabbitMQ but are OK with this risk for now Thursday, November 14, 13
  • WHERE TO GO FOR HELP ✓ ✓IRC: #sensu - freenode sensu-users mailing list ✓ http://docs.sensuapp.org Thursday, November 14, 13
  • QUESTIONS Thursday, November 14, 13
  • THANK YOU bethany@paperlesspost.com @skymob - twitter robotwitharose - #sensu on IRC (freenode) Thursday, November 14, 13