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Autoscale without netscaler_ccceu13
This document discusses autoscaling without NetScaler. It describes using XenServer API Round Robin Databases (RRDs) to reproduce the load balancing and monitoring capabilities of NetScaler for autoscaling. The document explains that RRDs store performance metrics on a per-host and per-VM basis. It details how CloudStack can query the RRDs over HTTP to monitor service groups and trigger scaling based on predefined policies, similar to how NetScaler operates with autoscaling. It provides examples of downloading whole RRDs and updates from the RRDs to retrieve monitoring data for hosts and VMs.
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Autoscale without netscaler_ccceu13
- 1. AutoScale without NetScaler Tuna- @ngtuna11
- 2. Agenda • AutoScale withNetScaler – Glossary – Top-level operation • AutoScale without NetScaler – Xapi RRDs – Demo
- 3.
- 4. Glossary Counter Condition AutoScale Policy AutoScale VMProfile AutoScale VM Group Timing parameters: Duration Interval Source: https://cwiki.apache.org/confluence/display/CLOUDSTACK/Autosc aling Quiet time Destroy vm grace period
- 5. NetScaler entity contains 3components: • • • A Load Balancing virtual server A Service Group Monitors Steps: 1. 2. 3. 4. 5. 6. Source: http://support.citrix.com/proddocs/topic/ns-system-10-1map/ns-autoscale-how-autoscale-works-con.html CS uses NetScaler API to push AutoScale configuration NetScaler calls CS API requests to deploy min number of VMs CS provisions min number of VMs on hypervisor NetScaler discovers the newly created VM's IP addresses, binds them into service group and loadbalances traffic to VMs NetScaler monitors service group by collecting SNMP metrics from the VMs NetScaler triggers scale-up or scale-down events based-on pre-defined policies at step 1.
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- 7. What is it? a native solution reproduce NetScaler AutoScale engine operation
- 8. Reproduce Load Balancing VirtualServer Virtual Router’s HAProxy NetScaler / SNMP Monitor XenServer API RRDs Service Group Apache CloudStack code Configuration Parameters
- 9. Xapi RRDs • Round RobinDatabases – • • • • Store performance metrics on a per host and a per VM basis Can be queried over HTTP or the RRD2CSV tool XenCenter uses this data to produce system performance graphs Data granularity – – – – • Consist of Round Robin Archieves (RRAs) in a fixed size database Every 5s for the duration of 10min Every min for the pass 2h Every hour for the pass week Every day for the pass year Consolidation Functions – – – AVERAGE MIN MAX Source: http://wiki.xen.org/wiki/XAPI_RRDs http://support.citrix.com/servlet/KbServlet/download/34969-102704897/reference.pdf http://www.xenserver.org/partners/developing-products-for-xenserver/18-sdkdevelopment/96-xs-dev-rrds.html
- 10. Steps: 1. 2. 3. 4. 5. 6. Users submit AutoScale configurationusing CloudStack API CS provisions min number of VMs on hypervisor CS provisions min number of VMs on hypervisor CloudStack binds the new VM into service group and loadbalances traffic to VMs using HAProxy on VirtualRouter CloudStack monitors service group by collecting metrics from the VMs via Xapi RRDs CloudStack triggers scale-up or scale-down events based-on pre-defined policies at step 1.
- 11. Getting RRDs overHTTP • Downloading the whole RRD – Downloading a Host RRD wget http://<server>/host_rrd?session_id=OpaqueRef:<SESSION HANDLE> – Downloading a VM RRD wget http://<server>/vm_rrd?session_id=OpaqueRef:<SESSION HANDLE>&uuid=<VM UUID>
- 12. Getting RRDs overHTTP • Getting update from the RRD – Downloading RRD update for a Host wget http://<server>/rrd_updates?session_id=OpaqueRef:<SESSION HANDLE>&start=10258122541&host=true – Downloading RRD update for all VMs wget http://<server>/rrd_updates?session_id=OpaqueRef:<SESSION HANDLE>&start=10258122541 – Downloading RRD update specifying CF wget http://<server>/rrd_updates?session_id=OpaqueRef:<SESSION HANDLE>&start=10258122541&cf=AVERAGE
- 13.
Editor's Notes
- #6 Step 6: As part of the scale-up trigger, the NetScalerAutoScale engine sends an API request to CloudPlatform to deploy a new VM. After the virtual machine is deployed, the AutoScale engine binds the service representing the VM (IP address and port) to the service group and, after the configured quiet time, starts forwarding load balanced traffic to the new virtual machine. Likewise, as part of the scale-down trigger, the NetScalerAutoScale engine selects a VM, stops forwarding new requests to that instance, and waits for the configured quiet time (to allow for the processing of current requests to complete) before it sends an API request to CloudPlatform to destroy the chosen instance.
- #10 rrd_updates will only give you what it considers to be the most appropriate archive for your request. As stated above, there are 4 archives available: one with 5 second updates for a maximum of 10 minutes, 1 minute for 2 hours, 1 hour for 1 week and 1 day for 1 year. When you do the GET, you specify on the URL the 'start' parameter, and it uses this to see which archive to give you. So if you specify a since value that is 9 minutes before 'now', you'll get 108 rows from the 10 minute archive, but if you specify 11 minutes before 'now', you'll get 11 rows from the 2 hour archive. In particular, it's important that you use the same definition of 'now' that the server is using, since the server is likely to be in GMT and your client may be in a different time zone. Each call to rrd_updates will return a value (in the 'end' XML tag) that can be used as the 'start' parameter for the next call.