Run locally<\/h2>\n\n\n\n
Check out the repository, run It will allocate the default 100MiB of RAM and wait for additional instances to connect:<\/p>\n\n\n\n Starting a second instance will share the “load” across instances:<\/p>\n\n\n\n Increase the workload (this is what should trigger the autoscaler later) using curl:<\/p>\n\n\n\n All instances should get the new workload size now:<\/p>\n\n\n\n Stopping the main instance will result in a re-election workflow (not too suffisticated, yet, but it should keep the workload size):<\/p>\n\n\n\n Since there are only two instances left, the workload per instance is increased.<\/p>\n\n\n\n A metrics endpoint is available so you can observe the application using prometheus:<\/p>\n\n\n\n Resources in the deploy folder can be used to run it on a Kubernetes or OpenShift cluster.<\/p>\n\n\n\n The deployment in The horizontal pod autoscaler in Using the route, you can scale the workload with curl as shown above:<\/p>\n\n\n\n The servicemonitor in you can see how the chunk size first went up when the workload was increased, and then back down when the autoscaler kicked in and scaled the deployment.<\/p>","protected":false},"excerpt":{"rendered":"To test out the horizontal pod autoscaling I built a simple example application that shares “load” across instances. The load is as simple as allocating a configurable chunk of memory. When the load increases, the pod autoscaler would spin up new instances so the chunks get smaller and the target is reached. You can find… Artikel ansehen<\/a>","protected":false},"author":1,"featured_media":360,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"_links":{"self":[{"href":"https:\/\/ntlx.org\/de\/wp-json\/wp\/v2\/posts\/358"}],"collection":[{"href":"https:\/\/ntlx.org\/de\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ntlx.org\/de\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ntlx.org\/de\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ntlx.org\/de\/wp-json\/wp\/v2\/comments?post=358"}],"version-history":[{"count":2,"href":"https:\/\/ntlx.org\/de\/wp-json\/wp\/v2\/posts\/358\/revisions"}],"predecessor-version":[{"id":362,"href":"https:\/\/ntlx.org\/de\/wp-json\/wp\/v2\/posts\/358\/revisions\/362"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/ntlx.org\/de\/wp-json\/wp\/v2\/media\/360"}],"wp:attachment":[{"href":"https:\/\/ntlx.org\/de\/wp-json\/wp\/v2\/media?parent=358"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ntlx.org\/de\/wp-json\/wp\/v2\/categories?post=358"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ntlx.org\/de\/wp-json\/wp\/v2\/tags?post=358"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}make build<\/code> and start .\/pod-autoscaler-example<\/code>.<\/p>\n\n\n\n$ .\/pod-autoscaler-example \nCan't connect to main instance at localhost:8081, assuming there is none and acting as mainWaiting for server to be responding...\nInstance ID: main\nAllocating 100 Mi\nInstance ID: main Variable size: 100 Mi Allocated: 100 Mi\nInstance ID: main Variable size: 100 Mi Allocated: 100 Mi\nInstance ID: main Variable size: 100 Mi Allocated: 100 Mi\n<\/code><\/pre>\n\n\n\n$ .\/pod-autoscaler-example \nInstance ID: nXii9k5RhdcdwYcBKw6hRT\nCan't run worker server, assuming we run on one host: listen tcp :8081: bind: address already in useAllocating 50 Mi\nInstance ID: nXii9k5RhdcdwYcBKw6hRT Variable size: 50 Mi Allocated: 50 Mi\nInstance ID: nXii9k5RhdcdwYcBKw6hRT Variable size: 50 Mi Allocated: 50 Mi\nInstance ID: nXii9k5RhdcdwYcBKw6hRT Variable size: 50 Mi Allocated: 50 Mi\nInstance ID: nXii9k5RhdcdwYcBKw6hRT Variable size: 50 Mi Allocated: 50 Mi\n<\/code><\/pre>\n\n\n\n$ curl localhost:8081\/set?mem=300\n<\/code><\/pre>\n\n\n\nAllocating 150 Mi\nInstance ID: nXii9k5RhdcdwYcBKw6hRT Variable size: 150 Mi Allocated: 150 Mi\nInstance ID: nXii9k5RhdcdwYcBKw6hRT Variable size: 150 Mi Allocated: 150 Mi\nInstance ID: nXii9k5RhdcdwYcBKw6hRT Variable size: 150 Mi Allocated: 150 Mi\n<\/code><\/pre>\n\n\n\nError sending request to getInstanceInfo: Get \"http:\/\/192.168.178.46:8082\/getInstanceInfo\": dial tcp 192.168.178.46:8082: connect: connection refused\nAssuming main is not responding anymore. Checking who can take over.\nNew main: nXii9k5RhdcdwYcBKw6hRT My ID: nXii9k5RhdcdwYcBKw6hRT\nTaking over...\nWaiting for server to be responding...\nInstance ID: main\nAllocating 300 Mi\nInstance ID: main Variable size: 300 Mi Allocated: 300 Mi\nInstance ID: main Variable size: 300 Mi Allocated: 300 Mi\n<\/code><\/pre>\n\n\n\n$ curl localhost:8081\/metrics\ninstances_count 2\nworkload_mib 300\nchunksize_mib 150\n<\/code><\/pre>\n\n\n\n<\/a>Running on OpenShift\/Kubernetes<\/h2>\n\n\n\n
deploy.yaml<\/code><\/a> will create a single instance, the service and route (svc.yaml<\/code><\/a> and route.yaml<\/code><\/a>) are used to expose it. Note that the command passes the service hostname and port to the containers so they can initiate communication when new instances come up.<\/p>\n\n\n\nhpa.yaml<\/code><\/a> will increase and decrease instances as necessary when the load increases\/decreases.<\/p>\n\n\n\n$ curl pod-autoscaler-example-autoscaler-example.apps.mycluster.com\/set?mem=200\n<\/code><\/pre>\n\n\n\nservicemonitor.yaml<\/code><\/a> makes the metrics available for Prometheus. When using OpenShift, you can query them in the OpenShift console:<\/p>\n\n\n\n![\"\"](\"https:\/\/ntlx.org\/wp-content\/uploads\/2022\/11\/metrics-700x358.png\")
<\/figure>\n\n\n\n