{"version":"1.0","provider_name":"UCT HPC","provider_url":"https:\/\/ucthpc.uct.ac.za","author_name":"Andrew Lewis","author_url":"https:\/\/ucthpc.uct.ac.za\/index.php\/author\/andrew-lewis\/","title":"AWS postscript - UCT HPC","type":"rich","width":600,"height":338,"html":"<blockquote class=\"wp-embedded-content\" data-secret=\"yHnP5w9BFb\"><a href=\"https:\/\/ucthpc.uct.ac.za\/index.php\/2012\/11\/06\/aws-postscript\/\">AWS postscript<\/a><\/blockquote><iframe sandbox=\"allow-scripts\" security=\"restricted\" src=\"https:\/\/ucthpc.uct.ac.za\/index.php\/2012\/11\/06\/aws-postscript\/embed\/#?secret=yHnP5w9BFb\" width=\"600\" height=\"338\" title=\"&#8220;AWS postscript&#8221; &#8212; UCT HPC\" data-secret=\"yHnP5w9BFb\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\" class=\"wp-embedded-content\"><\/iframe><script type=\"text\/javascript\">\n\/*! This file is auto-generated *\/\n!function(c,d){\"use strict\";var e=!1,o=!1;if(d.querySelector)if(c.addEventListener)e=!0;if(c.wp=c.wp||{},c.wp.receiveEmbedMessage);else if(c.wp.receiveEmbedMessage=function(e){var t=e.data;if(!t);else if(!(t.secret||t.message||t.value));else if(\/[^a-zA-Z0-9]\/.test(t.secret));else{for(var r,s,a,i=d.querySelectorAll('iframe[data-secret=\"'+t.secret+'\"]'),n=d.querySelectorAll('blockquote[data-secret=\"'+t.secret+'\"]'),o=new RegExp(\"^https?:$\",\"i\"),l=0;l<n.length;l++)n[l].style.display=\"none\";for(l=0;l<i.length;l++)if(r=i[l],e.source!==r.contentWindow);else{if(r.removeAttribute(\"style\"),\"height\"===t.message){if(1e3<(s=parseInt(t.value,10)))s=1e3;else if(~~s<200)s=200;r.height=s}if(\"link\"===t.message)if(s=d.createElement(\"a\"),a=d.createElement(\"a\"),s.href=r.getAttribute(\"src\"),a.href=t.value,!o.test(a.protocol));else if(a.host===s.host)if(d.activeElement===r)c.top.location.href=t.value}}},e)c.addEventListener(\"message\",c.wp.receiveEmbedMessage,!1),d.addEventListener(\"DOMContentLoaded\",t,!1),c.addEventListener(\"load\",t,!1);function t(){if(o);else{o=!0;for(var e,t,r,s=-1!==navigator.appVersion.indexOf(\"MSIE 10\"),a=!!navigator.userAgent.match(\/Trident.*rv:11\\.\/),i=d.querySelectorAll(\"iframe.wp-embedded-content\"),n=0;n<i.length;n++){if(!(r=(t=i[n]).getAttribute(\"data-secret\")))r=Math.random().toString(36).substr(2,10),t.src+=\"#?secret=\"+r,t.setAttribute(\"data-secret\",r);if(s||a)(e=t.cloneNode(!0)).removeAttribute(\"security\"),t.parentNode.replaceChild(e,t);t.contentWindow.postMessage({message:\"ready\",secret:r},\"*\")}}}}(window,document);\n<\/script>\n","description":"So after waiting 24 hours and then looking at the AWS billing reports a couple of things stand out. At first we were puzzled as to why we were billed for Run Instances as well as Spot Instances. &nbsp;Turns out that when you launch a cluster the head node will be provisioned identically to the worker nodes unless you specify a different image type. The config entries below will create a cluster with 5 worker nodes and 1 head node.CLUSTER_SIZE = 6NODE_IMAGE_ID = ami-999d49f0NODE_INSTANCE_TYPE = m2.2xlargeMASTER_INSTANCE_TYPE = m1.smallMASTER_IMAGE_ID = ami-899d49e0The worker nodes will be 64 bit 13xEC2 servers and the head node will be a 32 bit 1xEC2 server. &nbsp;This means you won't be billed disproportionately for a very powerful head node when a smaller instance will do. &nbsp;Bear in mind that the head node is not a Spot Instance only the worker nodes are so you need to factor this into your cost estimate. &nbsp;Also remember that for large or very busy clusters a more powerful head node may be required.As an aside, yesterday's test came to $3.67 (about 29 ZAR).The table above indicates the rather large cost saving one can achieve by making use of Spot Instances. &nbsp;This is based on our test yesterday. &nbsp;The Run Instance column is what one would&nbsp;pay for a guaranteed instance. &nbsp;","thumbnail_url":"https:\/\/ucthpc.uct.ac.za\/wp-content\/uploads\/2015\/07\/spotcosts.jpg"}