{"id":22190,"date":"2019-03-28T10:00:12","date_gmt":"2019-03-28T01:00:12","guid":{"rendered":"https:\/\/www.techscore.com\/blog\/?p=22190"},"modified":"2019-03-28T13:53:41","modified_gmt":"2019-03-28T04:53:41","slug":"raft-consensus-algorithm","status":"publish","type":"post","link":"https:\/\/www.techscore.com\/blog\/2019\/03\/28\/raft-consensus-algorithm\/","title":{"rendered":"Raft - Kubernetes(etcd)\u306eHA\u69cb\u6210\u306f\u306a\u305c3\u53f0\u4ee5\u4e0a\uff1f"},"content":{"rendered":"<p>\u3053\u3093\u306b\u3061\u306f\u3002\u677e\u672c\u3067\u3059\u3002<\/p>\n<p>Kubernetes \u30b3\u30f3\u30c8\u30ed\u30fc\u30eb\u30d7\u30ec\u30fc\u30f3\u306e HA(High Available) \u69cb\u6210\u306f\u4e8c\u901a\u308a\u3042\u308a\u307e\u3059\u304c\u3001<a href=\"https:\/\/kubernetes.io\/docs\/setup\/independent\/high-availability\/#before-you-begin\">\u516c\u5f0f\u30c9\u30ad\u30e5\u30e1\u30f3\u30c8\u5185\u306b\u6b21\u306e\u3088\u3046\u306a\u8a18\u8ff0<\/a>\u304c\u3042\u308a\u3001\u3044\u305a\u308c\u306e\u65b9\u5f0f\u3067\u3082 3 \u53f0\u4ee5\u4e0a\u306e\u30de\u30b7\u30f3\u3067\u30af\u30e9\u30b9\u30bf\u30fc\u3092\u69cb\u6210\u3059\u308b\u3053\u3068\u304c\u6c42\u3081\u3089\u308c\u3066\u3044\u307e\u3059\u3002<\/p>\n<blockquote><p>\n  For both methods you need this infrastructure:<\/p>\n<p>  <strong>Three machines<\/strong> that meet kubeadm\u2019s minimum requirements for the masters<\/p>\n<p>  \uff08\u4e2d\u7565\uff09<\/p>\n<p>  For the external etcd cluster only, you also need:<\/p>\n<p>  <strong>Three additional machines<\/strong> for etcd members\n<\/p><\/blockquote>\n<p>\u3053\u306e\u3001<strong>\u6700\u5c0f\u304c \"three\" \u3067\u3042\u308b\u5fc5\u8981\u6027<\/strong>\u306f\u3001\u3069\u3053\u304b\u3089\u304f\u308b\u5236\u7d04\u306a\u306e\u3067\u3057\u3087\u3046\u304b\u3002\"two\" \u3058\u3083\u3060\u3081\u306a\u306e\u3067\u3057\u3087\u3046\u304b\u3002<\/p>\n<p>\u4e8c\u901a\u308a\u306e HA \u69cb\u6210\u3068\u306f\u6b21\u306e\u901a\u308a\u3067\u3001\u305d\u306e\u4e3b\u306a\u9055\u3044\u306f etcd \u30af\u30e9\u30b9\u30bf\u30fc\u306e\u69cb\u6210\u65b9\u6cd5\u3067\u3042\u308b\u3053\u3068\u304c\u308f\u304b\u308a\u307e\u3059\u3002<\/p>\n<ul>\n<li><strong>Stacked etcd topology<\/strong> - \u30b9\u30bf\u30c3\u30af\u5316\u3055\u308c\u305f\u30b3\u30f3\u30c8\u30ed\u30fc\u30eb\u30d7\u30ec\u30fc\u30f3\u30ce\u30fc\u30c9\u306e\u5185\u90e8\u306b\u305d\u308c\u305e\u308c etcd \u3092\u914d\u7f6e\u3057\u3066\u30af\u30e9\u30b9\u30bf\u30fc\u3092\u69cb\u6210<\/li>\n<li><strong>External etcd topology<\/strong> - \u30b3\u30f3\u30c8\u30ed\u30fc\u30eb\u30d7\u30ec\u30fc\u30f3\u306e\u5916\u90e8\u306b etcd \u30af\u30e9\u30b9\u30bf\u30fc\u3092\u69cb\u6210<\/li>\n<\/ul>\n<p><a href=\"https:\/\/kubernetes.io\/docs\/setup\/independent\/ha-topology\/\">\u516c\u5f0f\u30c9\u30ad\u30e5\u30e1\u30f3\u30c8\u5185\u306e\u56f3<\/a>\uff08\u00a9 2019 <a href=\"https:\/\/kubernetes.io\/\">The Kubernetes<\/a>(<a href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY 4.0<\/a>)\uff09\u306e\u7dd1\u306e\u30a8\u30ea\u30a2\u304c etcd \u30af\u30e9\u30b9\u30bf\u30fc\u3067\u3059\u3002<\/p>\n<p><a href=\"https:\/\/www.techscore.com\/blog\/wp\/wp-content\/uploads\/2019\/03\/kubeadm-ha-topology-stacked-etcd.png\" rel=\"facebox\" rel=\"attachment wp-att-22248\"><img loading=\"lazy\" src=\"https:\/\/www.techscore.com\/blog\/wp\/wp-content\/uploads\/2019\/03\/kubeadm-ha-topology-stacked-etcd.png\" alt=\"\" width=\"400\" height=\"300\" class=\"aligncenter size-full wp-image-22248\" srcset=\"https:\/\/www.techscore.com\/blog\/wp\/wp-content\/uploads\/2019\/03\/kubeadm-ha-topology-stacked-etcd.png 800w, https:\/\/www.techscore.com\/blog\/wp\/wp-content\/uploads\/2019\/03\/kubeadm-ha-topology-stacked-etcd-300x225.png 300w, https:\/\/www.techscore.com\/blog\/wp\/wp-content\/uploads\/2019\/03\/kubeadm-ha-topology-stacked-etcd-768x576.png 768w\" sizes=\"(max-width: 400px) 100vw, 400px\" \/><\/a><\/p>\n<p><a href=\"https:\/\/www.techscore.com\/blog\/wp\/wp-content\/uploads\/2019\/03\/kubeadm-ha-topology-external-etcd.png\" rel=\"facebox\" rel=\"attachment wp-att-22249\"><img loading=\"lazy\" src=\"https:\/\/www.techscore.com\/blog\/wp\/wp-content\/uploads\/2019\/03\/kubeadm-ha-topology-external-etcd.png\" alt=\"\" width=\"400\" height=\"300\" class=\"aligncenter size-full wp-image-22249\" srcset=\"https:\/\/www.techscore.com\/blog\/wp\/wp-content\/uploads\/2019\/03\/kubeadm-ha-topology-external-etcd.png 800w, https:\/\/www.techscore.com\/blog\/wp\/wp-content\/uploads\/2019\/03\/kubeadm-ha-topology-external-etcd-300x225.png 300w, https:\/\/www.techscore.com\/blog\/wp\/wp-content\/uploads\/2019\/03\/kubeadm-ha-topology-external-etcd-768x576.png 768w\" sizes=\"(max-width: 400px) 100vw, 400px\" \/><\/a><\/p>\n<p>\u305d\u3053\u3067\u3001<a href=\"https:\/\/github.com\/etcd-io\/etcd\">etcd \u306e\u30c9\u30ad\u30e5\u30e1\u30f3\u30c8<\/a>\u3092\u898b\u3066\u307f\u308b\u3068\u3001HA \u69cb\u6210\u306e\u5b9f\u73fe\u306b <strong>Raft consensus algorithm<\/strong> \u3092\u63a1\u7528\u3057\u3066\u3044\u308b\u3053\u3068\u304c\u308f\u304b\u308a\u307e\u3057\u305f\u3002<\/p>\n<blockquote><p>\n  etcd is written in Go and <strong>uses the Raft consensus algorithm to manage a highly-available replicated log<\/strong>.\n<\/p><\/blockquote>\n<p>\u672c\u8a18\u4e8b\u306f\u3001\u3053\u306e Raft \u3092\u7d10\u89e3\u304f\u3053\u3068\u3067 \"three\" \u306e\u610f\u5473\u3092\u7406\u89e3\u3057\u3088\u3046\u3068\u3044\u3046\u3001\u79c1\u306e\u500b\u4eba\u7684\u306a\u8da3\u5473\u306b\u3088\u308b\u63a2\u7d22\u306e\u30e1\u30e2\u3067\u3059\u3002<\/p>\n<p>\u4e3b\u306a\u53c2\u8003\u8cc7\u6599\uff1a<\/p>\n<ul>\n<li><a href=\"https:\/\/ramcloud.stanford.edu\/raft.pdf\">In Search of an Understandable Consensus Algorithm (Extended Version) | Diego Ongaro and John Ousterhout | Stanford University<\/a><\/li>\n<\/ul>\n<h2>State Machine Replication \u3068\u5206\u6563\u5408\u610f\u30a2\u30eb\u30b4\u30ea\u30ba\u30e0<\/h2>\n<p><strong>\u9ad8\u53ef\u7528\u6027\uff08Hight availability\uff09<\/strong>\u306e\u5b9f\u73fe\u306a\u3069\u3092\u76ee\u7684\u306b\u3001\u30b9\u30c6\u30fc\u30c8\u30d5\u30eb\u306a\u30b5\u30fc\u30d3\u30b9\u3092\u3001\u540c\u3058\u6a5f\u80fd\u3068\u72b6\u614b\u3092\u6301\u3064\u8907\u6570\u306e\u30ce\u30fc\u30c9\u3067\u69cb\u6210\u3055\u308c\u308b<strong>\u5206\u6563\u30b5\u30fc\u30d3\u30b9<\/strong>\uff08<strong>\u30ec\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3<\/strong>\uff09\u3068\u3057\u3066\u8a2d\u8a08\u3059\u308b\u5834\u5408\u3001\u5404\u30ce\u30fc\u30c9\u4e0a\u3067\u52d5\u4f5c\u3059\u308b\u30b5\u30fc\u30d3\u30b9\u306e\u4e00\u8cab\u6027\u4fdd\u8a3c\u304c\u8ab2\u984c\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n<p>\u3053\u306e\u6642\u3001\u30b5\u30fc\u30d3\u30b9\u306e\u7279\u6027\u304c<strong>\u6c7a\u5b9a\u8ad6\u7684<\/strong>\u3067\u3042\u308b\u3068\u5b9a\u7fa9\u3067\u304d\u308c\u3070\u3001\u540c\u3058\u958b\u59cb\u72b6\u614b\u304b\u3089\u540c\u3058\u9806\u5e8f\u3067\u547d\u4ee4\uff08\u5165\u529b\uff09\u3092\u53d7\u3051\u53d6\u308b\u3053\u3068\u3067\u3001\u3069\u306e\u30b5\u30fc\u30d3\u30b9\u3082\u540c\u3058\u72b6\u614b\u306b\u5230\u9054\u3057\u3001\u540c\u3058\u5fdc\u7b54\uff08\u51fa\u529b\uff09\u3092\u8fd4\u3059\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002\u3053\u306e\u8003\u3048\u306b\u57fa\u3065\u3044\u305f\u8a2d\u8a08\u3092 <strong><a href=\"https:\/\/en.wikipedia.org\/wiki\/State_machine_replication\">State machine replication<\/a><\/strong> \u3068\u304b\u3001<strong>State machine approach<\/strong> \u3068\u547c\u3073\u307e\u3059\u3002\u524d\u8ff0\u306e\u3088\u3046\u306a\u500b\u3005\u306e\u30ce\u30fc\u30c9\u4e0a\u3067\u52d5\u4f5c\u3059\u308b\u30b5\u30fc\u30d3\u30b9\u304c <strong>State machine<\/strong> \u3067\u3059\u3002<\/p>\n<p>state machine replication \u306b\u304a\u3051\u308b\u5404\u30ce\u30fc\u30c9\u306f\u901a\u5e38\u3001state machine \u304c\u5b9f\u884c\u3059\u308b\u547d\u4ee4\u3092\u30a8\u30f3\u30c8\u30ea\u3068\u3057\u3066\u30ed\u30b0\u306b\u683c\u7d0d\u3057\u3001\u9806\u756a\u901a\u308a\u306b state machine \u306b\u9069\u7528\u3057\u307e\u3059\u3002\u3053\u306e\u3001\u30af\u30e9\u30b9\u30bf\u30fc\u5185\u306e\u30ce\u30fc\u30c9\u304c\u30ed\u30b0\u3092\u8907\u88fd\u3057\u3001state machine \u306b\u9069\u7528\u3059\u308b\u305f\u3081\u306e<strong>\u5206\u6563\u5408\u610f\u30a2\u30eb\u30b4\u30ea\u30ba\u30e0<\/strong>\u304c Raft \u3067\u3059\u3002<\/p>\n<h2>Raft - \u57fa\u672c\u4e8b\u9805<\/h2>\n<h3>\u30b9\u30c6\u30fc\u30bf\u30b9<\/h3>\n<p>Raft \u30af\u30e9\u30b9\u30bf\u30fc\u5185\u306e\u30ce\u30fc\u30c9\u306b\u306f\u3001\u4e09\u3064\u306e\u30b9\u30c6\u30fc\u30bf\u30b9\u304c\u5b58\u5728\u3057\u307e\u3059\u3002<\/p>\n<ul>\n<li><strong>leader<\/strong> - \u30ea\u30fc\u30c0\u30fc<\/li>\n<li><strong>candidate<\/strong> - \u30ea\u30fc\u30c0\u30fc\u5019\u88dc<\/li>\n<li><strong>follower<\/strong> - \u30d5\u30a9\u30ed\u30ef\u30fc<\/li>\n<\/ul>\n<p>\u901a\u5e38\u3001\u30af\u30e9\u30b9\u30bf\u30fc\u5185\u306e leader \u306f\u4e00\u53f0\u3060\u3051\u3067\u3001\u305d\u306e\u4ed6\u306e\u30ce\u30fc\u30c9\u306f\u5168\u3066 follower \u3067\u3059\u3002leader \u304c\u30af\u30e9\u30a4\u30a2\u30f3\u30c8\u306e\u30ea\u30af\u30a8\u30b9\u30c8\u3092\u5168\u3066\u51e6\u7406\u3057\u307e\u3059\u3002\u3082\u3057\u30af\u30e9\u30a4\u30a2\u30f3\u30c8\u306e\u30ea\u30af\u30a8\u30b9\u30c8\u304c follower \u306b\u5c4a\u3051\u3070\u3001\u30ea\u30af\u30a8\u30b9\u30c8\u306f leader \u306b\u30ea\u30c0\u30a4\u30ec\u30af\u30c8\u3055\u308c\u307e\u3059\u3002<\/p>\n<p>\u65b0\u3057\u3044 leader \u3092\u9078\u51fa\u3059\u308b\u305f\u3081\u306b\u7acb\u5019\u88dc\u3057\u305f\u30ce\u30fc\u30c9\u304c candidate \u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n<h3>RPC<\/h3>\n<p>Raft \u3067\u6271\u3046 RPC \u306f\u57fa\u672c\u7684\u306b\u6b21\u306e 2 \u3064\u3067\u3001\u30e1\u30c3\u30bb\u30fc\u30b8\u30bf\u30a4\u30d7\u306f 4 \u3064\uff08\u5404 RPC \u306e\u30ea\u30af\u30a8\u30b9\u30c8\u30e1\u30c3\u30bb\u30fc\u30b8\u3068\u30ec\u30b9\u30dd\u30f3\u30b9\u30e1\u30c3\u30bb\u30fc\u30b8\uff09\u3057\u304b\u3042\u308a\u307e\u305b\u3093\u3002<\/p>\n<ul>\n<li><strong>RequestVote RPC<\/strong> - leader \u306b\u306a\u308b\u305f\u3081\u306b candidate \u304c\u767a\u884c\u3059\u308b RPC<\/li>\n<li><strong>AppendEntries RPC<\/strong> - \u30ed\u30b0\u306e\u8907\u88fd\u306e\u305f\u3081\u306b leader \u304c\u767a\u884c\u3059\u308b RPC<\/li>\n<\/ul>\n<p>leader \u306f\u3001\u30ed\u30b0\u30a8\u30f3\u30c8\u30ea\u3092\u542b\u307e\u306a\u3044 AppendEntries RPC \u3092 <strong>heartbeat<\/strong> \u3068\u3057\u3066\u5b9a\u671f\u7684\u306b\u30af\u30e9\u30b9\u30bf\u30fc\u5185\u306e\u4ed6\u306e\u30ce\u30fc\u30c9\u306b\u5411\u3051\u767a\u884c\u3057\u307e\u3059\u3002<\/p>\n<h3>term<\/h3>\n<p>Raft \u306f\u3001\u5f8c\u8ff0\u3059\u308b leader election \u306e\u958b\u59cb\u304b\u3089\u3001\u9078\u51fa\u3055\u308c\u305f leader \u304c\u5b58\u7d9a\u3059\u308b\u671f\u9593\u306b <strong>term<\/strong> \u3068\u547c\u3076\u756a\u53f7\u3092\u5272\u308a\u5f53\u3066\u3066\u3044\u307e\u3059\u3002leader \u304c\u78ba\u5b9a\u305b\u305a\u3001leader \u4e0d\u5728\u3067\u7d42\u4e86\u3059\u308b term \u3082\u5b58\u5728\u3057\u307e\u3059\u3002<\/p>\n<p>term \u306f 0 \u304b\u3089\u59cb\u307e\u308a\u30011 \u305a\u3064\u30a4\u30f3\u30af\u30ea\u30e1\u30f3\u30c8\u3055\u308c\u307e\u3059\u3002<\/p>\n<h3>log<\/h3>\n<p>\u30ce\u30fc\u30c9\u306f\u3001state machine \u306b\u9069\u7528\u3059\u308b\u305f\u3081\u306e\u547d\u4ee4\u3092\u3001\u30ed\u30fc\u30ab\u30eb\u5185\u306b\u4fdd\u5b58\u3057\u3066\u3044\u307e\u3059\u3002\u3053\u306e\u547d\u4ee4\u306e\u30b3\u30ec\u30af\u30b7\u30e7\u30f3\u3092 log \u3068\u547c\u3073\u3001log \u5185\u306e\u30a8\u30f3\u30c8\u30ea\u306b\u306f\u305d\u308c\u305e\u308c\u3001leader \u304c\u305d\u306e\u30a8\u30f3\u30c8\u30ea\u3092\u4fdd\u5b58\u3057\u305f\u969b\u306e term \u3068\u3001\u30a8\u30f3\u30c8\u30ea\u3092\u8b58\u5225\u3059\u308b\u305f\u3081\u306e index \u304c\u8a18\u9332\u3055\u308c\u307e\u3059\u3002<\/p>\n<h2>The Raft Consensus Algorithm<\/h2>\n<p>\u5408\u610f\u30a2\u30eb\u30b4\u30ea\u30ba\u30e0\u306f\u6b21\u306e\u4e8c\u3064\u306e\u30e1\u30ab\u30cb\u30ba\u30e0\u3067\u69cb\u6210\u3055\u308c\u3066\u3044\u307e\u3059\u3002<\/p>\n<ul>\n<li><strong>Leader Election<\/strong> - \u6709\u52b9\u306a leader \u306e\u4e0d\u5728\u6642\u306b\u3001\u65b0\u305f\u306a leader \u3092\u6c7a\u5b9a\u3059\u308b<\/li>\n<li><strong>Log Replication<\/strong> - leader \u304c\u30af\u30e9\u30a4\u30a2\u30f3\u30c8\u304b\u3089\u53d7\u3051\u53d6\u3063\u305f log \u30a8\u30f3\u30c8\u30ea\u3092\u3001\u4ed6\u306e\u30ce\u30fc\u30c9\u306b\u8907\u88fd\u3059\u308b<\/li>\n<\/ul>\n<p>\u307e\u305f\u3001\u3053\u308c\u3089\u306e\u30e1\u30ab\u30cb\u30ba\u30e0\u306b\u304a\u3044\u3066\u3001Raft \u306f\u6b21\u306e\u7279\u6027\u304c\u5e38\u306b\u771f\u3067\u3042\u308b\u3053\u3068\u3092\u4fdd\u8a3c\u3057\u3066\u3044\u307e\u3059\u3002<\/p>\n<ul>\n<li><strong>Election Safety<\/strong> - 1 \u3064\u306e term \u306b leader \u306f 1 \u53f0\u307e\u3067<\/li>\n<li><strong>Leader Append-Only<\/strong> - leader \u306f\u30ed\u30fc\u30ab\u30eb\u306e log \u306b\u5bfe\u3057\u65b0\u305f\u306a\u8ffd\u8a18\u306e\u307f\u304c\u53ef\u80fd\u3067\u3001\u524a\u9664\u3084\u4e0a\u66f8\u304d\u306f\u3067\u304d\u306a\u3044<\/li>\n<li><strong>Log Matching<\/strong> - \u3075\u305f\u3064\u306e\u30ce\u30fc\u30c9\u306e log \u306b\u540c\u3058 term \u3068 index \u3092\u6301\u3064\u30a8\u30f3\u30c8\u30ea\u304c\u542b\u307e\u308c\u3066\u3044\u308b\u5834\u5408\u3001\u305d\u306e index \u307e\u3067\u306e\u5168\u3066\u306e\u30a8\u30f3\u30c8\u30ea\u306f\u4e21\u8005\u306e\u30ce\u30fc\u30c9\u3067\u4e00\u81f4\u3059\u308b<\/li>\n<li><strong>Leader Completeness<\/strong> - leader \u304c\u30b3\u30df\u30c3\u30c8\uff08\u5f8c\u8ff0\uff09\u3057\u305f log \u30a8\u30f3\u30c8\u30ea\u306f\u3001\u4ee5\u964d\u306e term \u306e leader \u304c\u6301\u3064 log \u306b\u5fc5\u305a\u542b\u307e\u308c\u308b<\/li>\n<li><strong>State Machine Safety<\/strong> - leader \u304c state machine \u306b\u9069\u7528\u3057\u305f log \u30a8\u30f3\u30c8\u30ea\u306b\u5bfe\u3057\u3001\u4ed6\u306e\u30ce\u30fc\u30c9\u304c\u3001\u540c\u3058 index \u3092\u6301\u3061\u5185\u5bb9\u306e\u7570\u306a\u308b\u30a8\u30f3\u30c8\u30ea\u3092 state machine \u306b\u9069\u7528\u3059\u308b\u3053\u3068\u306f\u306a\u3044<\/li>\n<\/ul>\n<h3>Leader Election \u306e\u30d5\u30ed\u30fc<\/h3>\n<ol>\n<li><strong>\u521d\u671f\u72b6\u614b\uff1a<\/strong>\u8d77\u52d5\u3055\u308c\u305f\u76f4\u5f8c\u306e\u30ce\u30fc\u30c9\u306e\u30b9\u30c6\u30fc\u30bf\u30b9\u306f\u5fc5\u305a follower \u3068\u306a\u308b\u3002\u3064\u307e\u308a\u3001\u30af\u30e9\u30b9\u30bf\u30fc\u8d77\u52d5\u5f8c\u306f\u5168\u30ce\u30fc\u30c9\u304c follower \u3067\u3042\u308a\u3001leader \u306f\u5b58\u5728\u3057\u306a\u3044\u3002<\/p>\n<\/li>\n<li>\n<p><strong>\u958b\u59cb\uff1a<\/strong>follower \u306f\u3001leader \u304b\u3089\u6700\u5f8c\u306b RPC \u3092\u53d7\u3051\u53d6\u3063\u3066\u304b\u3089 election timeout \u3068\u547c\u3070\u308c\u308b\u6642\u9593\u304c\u7d4c\u904e\u3059\u308b\u307e\u3067\u306b\u65b0\u305f\u306a RPC \u304c\u5c4a\u304b\u306a\u3051\u308c\u3070\u3001\u30af\u30e9\u30b9\u30bf\u30fc\u5185\u306b leader \u304c\u5b58\u5728\u3057\u306a\u3044\u3068\u5224\u65ad\u3057\u3001\u81ea\u3089\u306e\u30b9\u30c6\u30fc\u30bf\u30b9\u3092 candidate \u306b\u5909\u66f4\u3057\u3001term \u3092\u30a4\u30f3\u30af\u30ea\u30e1\u30f3\u30c8\u3057\u305f\u4e0a\u3067\u3001leader election \u3092\u958b\u59cb\u3059\u308b\u3002\u8907\u6570\u306e\u30ce\u30fc\u30c9\u304c\u540c\u6642\u306b candidate \u306b\u306a\u308b\u53ef\u80fd\u6027\u3092\u4e0b\u3052\u308b\u305f\u3081\u3001election timeout \u306f\u30ce\u30fc\u30c9\u3054\u3068\u306b\u30e9\u30f3\u30c0\u30e0\u3067\u6c7a\u5b9a\u3055\u308c\u308b\u3002<\/p>\n<\/li>\n<li>\n<p><strong>\u7acb\u5019\u88dc\uff1a<\/strong>candidate \u304b\u3089 leader \u306b\u72b6\u614b\u9077\u79fb\u3059\u308b\u306b\u306f\u3001\u30af\u30e9\u30b9\u30bf\u30fc\u5185\u306e\u904e\u534a\u6570\u306e\u30ce\u30fc\u30c9\u304b\u3089\u652f\u6301\u3092\u53d7\u3051\u308b\u5fc5\u8981\u304c\u3042\u308b\u3002candidate \u306f\u307e\u305a\u81ea\u5206\u81ea\u8eab\u306b\u6295\u7968\u3057\u3001\u7d9a\u3044\u3066\u30af\u30e9\u30b9\u30bf\u30fc\u5185\u306e\u4ed6\u306e\u30ce\u30fc\u30c9\u306b RequestVote RPC \u3092\u4e26\u5217\u3067\u767a\u884c\u3059\u308b\u3002<\/p>\n<\/li>\n<li>\n<p><strong>\u6295\u7968\uff1a<\/strong>candidate \u304b\u3089 RequestVote RPC \u3092\u53d7\u3051\u53d6\u3063\u305f\u30ce\u30fc\u30c9\u306f\u3001candidate \u304c leader \u306b\u306a\u308b\u3053\u3068\u3092\u627f\u8afe\u3059\u308b\u304b\u5426\u304b\u3092\u5fdc\u7b54\u3059\u308b\u3002\u6700\u65b0\u306e\u30ed\u30b0\u3092\u6301\u3064\u30ce\u30fc\u30c9\u304c leader \u306b\u9078\u3070\u308c\u308b\u3079\u304d\u306a\u306e\u3067\u3001RequestVote RPC \u3078\u306e\u5fdc\u7b54\u306f\u3001\u6b21\u306e\u4e8c\u3064\u3092\u3068\u3082\u306b\u6e80\u305f\u3059\u5834\u5408\u306b\u627f\u8afe\u3059\u308b\u3002<\/p>\n<ul>\n<li>candidate \u5074 term \u304c\u81ea\u8eab\u306e term \u4ee5\u4e0a\uff08candidate \u5074\u306e term \u306f RequestVote RPC \u306e\u5f15\u6570 <code>term<\/code> \u3068\u3057\u3066\u6e21\u3055\u308c\u308b\uff09<\/li>\n<li>candidate \u5074 log \u5185\u306e\u6700\u7d42\u30a8\u30f3\u30c8\u30ea\u304c\u30ed\u30fc\u30ab\u30eb\u306e log \u6700\u7d42\u30a8\u30f3\u30c8\u30ea\u3068\u540c\u3058\u304b\u3001\u305d\u308c\u3088\u308a\u65b0\u3057\u3044\uff08candidate \u5074\u306e\u6700\u7d42\u30a8\u30f3\u30c8\u30ea\u60c5\u5831\u306f\u3001RequestVote RPC \u306e\u5f15\u6570 <code>lastLogTerm<\/code> \u304a\u3088\u3073 <code>lastLogIndex<\/code> \u3068\u3057\u3066\u6e21\u3055\u308c\u308b\uff09<\/li>\n<\/ul>\n<\/li>\n<li><strong>\u7d50\u679c\u78ba\u5b9a\uff1a<\/strong>candidate \u306f\u3001\u6b21\u306e\u3044\u305a\u308c\u304b\u306b\u306a\u308b\u307e\u3067\u5f85\u6a5f\u3057\u3001\u305d\u306e\u5f8c\u3001leader election \u3092\u7d42\u4e86\u3059\u308b\u3002\n<ul>\n<li><strong>\u52dd\u5229\u3057\u305f<\/strong> - \u30af\u30e9\u30b9\u30bf\u30fc\u5185\u5168\u30ce\u30fc\u30c9\u306e\u904e\u534a\u6570\u304b\u3089\u627f\u8afe\u3092\u5f97\u308b\u3068\u52dd\u5229\u3068\u306a\u308b\u3002\u30b9\u30c6\u30fc\u30bf\u30b9\u3092 candidate \u304b\u3089 leader \u306b\u5909\u66f4\u3002\u305d\u306e\u5f8c\u3001\u4ed6\u306e\u30ce\u30fc\u30c9\u306b heartbeat \u3092\u6253\u3064\u3053\u3068\u3067\u65b0\u305f\u306a leader election \u306e\u767a\u751f\u3092\u9632\u3050<\/li>\n<li><strong>\u4ed6\u306b leader \u304c\u73fe\u308c\u305f<\/strong> - candidate \u304c\u4ed6\u306e\u30ce\u30fc\u30c9\u304b\u3089 AppendEntries RPC \u3092\u53d7\u3051\u53d6\u3063\u305f\u5834\u5408\u3001\u4ed6\u306b leader \u304c\u5b58\u5728\u3059\u308b\u3053\u3068\u3092\u793a\u3059\u3002\u30b9\u30c6\u30fc\u30bf\u30b9\u3092 candidate \u304b\u3089 follower \u306b\u5909\u66f4\u3002\u305f\u3060\u3057\u3001\u76f8\u624b\u306e term \u304c\u81ea\u8eab\u306e term \u3088\u308a\u5c0f\u3055\u3044\u5834\u5408\u306f\u3001\u62d2\u5426\u3059\u308b<\/li>\n<li><strong>\u52dd\u8005\u304c\u3044\u306a\u3044\u307e\u307e\u671f\u9593\u304c\u904e\u304e\u305f<\/strong> - candidate \u306f leader election \u958b\u59cb\u6642\u306b\u3082\u3001\u30e9\u30f3\u30c0\u30e0\u306a election timeout \u3092\u958b\u59cb\u3057\u3066\u3044\u308b\u3002\u904e\u534a\u6570\u306e\u627f\u8afe\u3092\u5f97\u306a\u3044\u307e\u307e\u30bf\u30a4\u30e0\u30a2\u30a6\u30c8\u3092\u8fce\u3048\u308b\u3068\u3001term \u3092\u30a4\u30f3\u30af\u30ea\u30e1\u30f3\u30c8\u3057\u3066\u65b0\u305f\u306a leader election \u3092\u958b\u59cb\u3059\u308b<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n<h3>Log Replication \u306e\u30d5\u30ed\u30fc<\/h3>\n<ol>\n<li><strong>\u8907\u88fd\u4f9d\u983c\uff1a<\/strong>\u30af\u30e9\u30a4\u30a2\u30f3\u30c8\u304b\u3089\u30ea\u30af\u30a8\u30b9\u30c8\u3092\u53d7\u3051\u305f leader \u306f\u3001\u305d\u306e\u5185\u5bb9\u3092\u65b0\u305f\u306a\u30a8\u30f3\u30c8\u30ea\u3068\u3057\u3066\u30ed\u30fc\u30ab\u30eb\u306e log \u306b\u8ffd\u52a0\u3059\u308b\u3002\u7d9a\u3044\u3066\u3001\u30af\u30e9\u30b9\u30bf\u30fc\u5185\u306e\u4ed6\u306e\u30ce\u30fc\u30c9\u306b AppendEntries RPC \u3092\u767a\u884c\u3057\u3066\u30a8\u30f3\u30c8\u30ea\u306e\u8907\u88fd\u3092\u8981\u6c42\u3059\u308b\u3002\u30cd\u30c3\u30c8\u30ef\u30fc\u30af\u969c\u5bb3\u3084\u30ce\u30fc\u30c9\u306e\u30af\u30e9\u30c3\u30b7\u30e5\u306a\u3069\u3067\u8907\u88fd\u8981\u6c42\u306b\u5931\u6557\u3057\u305f\u3089\u3001\u540c\u30ce\u30fc\u30c9\u306b\u5bfe\u3057 AppendEntries RPC \u3092\u7e70\u308a\u8fd4\u3057\u9001\u308a\u7d9a\u3051\u308b\u3002<\/p>\n<\/li>\n<li>\n<p><strong>\u8907\u88fd\uff1a<\/strong>AppendEntries RPC \u3092\u53d7\u3051\u53d6\u3063\u305f\u30ce\u30fc\u30c9\u306f\u3001\u30a8\u30f3\u30c8\u30ea\u3092\u30ed\u30fc\u30ab\u30eb\u306e log \u306b\u8ffd\u52a0\u3057\u3001leader \u306b\u5fdc\u7b54\u3092\u8fd4\u3059\u3002\u3053\u306e\u6642\u3001\u30a8\u30f3\u30c8\u30ea\u3092\u8ffd\u52a0\u3059\u308b\u306b\u306f\u6b21\u306e\u6761\u4ef6\u3092\u6e80\u305f\u3059\u5fc5\u8981\u304c\u3042\u308b\u3002<\/p>\n<ul>\n<li>leader \u5074\u306e term \u304c\u3001\u81ea\u8eab\u306e term \u4ee5\u4e0a\uff08leader \u5074\u306e term \u306f\u3001AppendEntries RPC \u306e\u5f15\u6570 <code>term<\/code> \u3068\u3057\u3066\u6e21\u3055\u308c\u308b\uff09<\/li>\n<li>\u8ffd\u52a0\u3057\u3088\u3046\u3068\u3057\u3066\u3044\u308b\u30a8\u30f3\u30c8\u30ea\u306e\u76f4\u524d\u306e\u30a8\u30f3\u30c8\u30ea\u304c\u30ed\u30fc\u30ab\u30eb\u306e log \u5185\u306b\u542b\u307e\u308c\u3066\u3044\u308b\uff08\u76f4\u524d\u306e\u30a8\u30f3\u30c8\u30ea\u306e index \u304c\u3001AppendEntries RPC \u306e\u5f15\u6570 <code>prevLogIndex<\/code> \u3068\u3057\u3066\u6e21\u3055\u308c\u308b\uff09<\/li>\n<\/ul>\n<p>\u6761\u4ef6\u3092\u6e80\u305f\u3055\u306a\u3044\u5834\u5408\u3001\u30ed\u30fc\u30ab\u30eb log \u306b\u30a8\u30f3\u30c8\u30ea\u3092\u8ffd\u52a0\u305b\u305a\u3001leader \u306b\u30a8\u30f3\u30c8\u30ea\u8ffd\u52a0\u5931\u6557\u3092\u5fdc\u7b54\u3068\u3057\u3066\u8fd4\u3059\u3002\u3053\u3046\u3059\u308b\u3053\u3068\u3067\u3001leader \u5074\u304c AppendEntries RPC \u3092\u4f7f\u3063\u3066\u3072\u3068\u3064\u53e4\u3044\u30a8\u30f3\u30c8\u30ea\u3092\u901a\u77e5\u3057\u3066\u304f\u308c\u308b\u3002\u307e\u305f\u3001\u8ffd\u52a0\u3057\u3088\u3046\u3068\u3057\u3066\u3044\u308b\u30a8\u30f3\u30c8\u30ea\u3068\u540c\u3058 index \u3092\u6301\u3064\u30a8\u30f3\u30c8\u30ea\u304c\u30ed\u30fc\u30ab\u30eb\u306e log \u306b\u542b\u307e\u308c\u3066\u3044\u308b\u5834\u5408\uff08\u30b3\u30f3\u30d5\u30ea\u30af\u30c8\uff09\u3001\u30ed\u30fc\u30ab\u30eb log \u5185\u306e\u305d\u308c\u4ee5\u964d\u306e\u30a8\u30f3\u30c8\u30ea\u3092\u5168\u3066\u524a\u9664\u3057\u305f\u4e0a\u3067\u3001\u65b0\u305f\u306a\u30a8\u30f3\u30c8\u30ea\u3092\u8ffd\u52a0\u3059\u308b\u3002<\/p>\n<\/li>\n<li>\n<p><strong>\u30b3\u30df\u30c3\u30c8\uff08leader\uff09\uff1a<\/strong>\u904e\u534a\u6570\u306e\u5fdc\u7b54\u3092\u53d7\u3051\u53d6\u3063\u305f leader \u306f\u3001\u30a8\u30f3\u30c8\u30ea\u3092\u30ed\u30fc\u30ab\u30eb\u306e state machine \u306b\u9069\u7528\u3059\u308b\u3002\u3053\u308c\u3092<strong>\u30b3\u30df\u30c3\u30c8<\/strong>\u3068\u8a00\u3046\u3002<\/p>\n<\/li>\n<li>\n<p><strong>\u30b3\u30df\u30c3\u30c8\uff08leader \u4ee5\u5916\uff09\uff1a<\/strong>leader \u304c\u30b3\u30df\u30c3\u30c8\u3057\u305f\u3053\u3068\u3092\u3001log replication \u3084 heartbeat \u306e\u305f\u3081\u306b\u767a\u884c\u3055\u308c\u305f AppendEntries RPC \u306b\u3088\u308a\u77e5\u3063\u305f follower \u306f\u3001\u30a8\u30f3\u30c8\u30ea\u3092\u30ed\u30fc\u30ab\u30eb\u306e state machine \u306b\u9069\u7528\u3059\u308b\u3002AppendEntries RPC \u306b\u306f leader \u304c\u6700\u5f8c\u306b\u30b3\u30df\u30c3\u30c8\u3057\u305f log \u30a8\u30f3\u30c8\u30ea\u306e index \u304c\u5f15\u6570 <code>leaderCommit<\/code> \u3068\u3057\u3066\u542b\u307e\u308c\u3066\u3044\u308b\u3002\u3053\u308c\u3068\u30ed\u30fc\u30ab\u30eb\u306e\u30b3\u30df\u30c3\u30c8 index \u3092\u6bd4\u8f03\u3057\u3001leader \u5074\u306b\u3042\u308f\u305b\u308b\u3002<\/p>\n<\/li>\n<\/ol>\n<h2>\u904e\u534a\u6570\u3068\u8010\u969c\u5bb3\u6027<\/h2>\n<p>\u4ee5\u4e0a\u306e\u3088\u3046\u306b\u3001leader election\u3001log replication \u3068\u3082\u306b\u30af\u30e9\u30b9\u30bf\u5185\u5168\u30ce\u30fc\u30c9\u306e\u904e\u534a\u6570\u304b\u3089\u306e\u627f\u8afe\u3092\u5fc5\u8981\u3068\u3057\u3066\u3044\u307e\u3059\u3002\u3053\u3046\u3059\u308b\u3053\u3068\u3067\u3001\u4f8b\u3048\u3070\u30cd\u30c3\u30c8\u30ef\u30fc\u30af\u304c\u5206\u65ad\u3055\u308c\u3066\u30b9\u30d7\u30ea\u30c3\u30c8\u30d6\u30ec\u30a4\u30f3\u306e\u72b6\u6cc1\u306b\u9665\u3063\u3066\u3082\u3001\u904e\u534a\u6570\u3092\u6e80\u305f\u3059\u5074\u306e\u30b0\u30eb\u30fc\u30d7\u3060\u3051\u3092\u6a5f\u80fd\u3055\u305b\u308b\u3053\u3068\u304c\u53ef\u80fd\u3068\u306a\u308a\u307e\u3059\u3002\u904e\u534a\u6570\u306b\u6e80\u305f\u306a\u3044\u5074\u306e\u30b0\u30eb\u30fc\u30d7\u306f\u30b3\u30df\u30c3\u30c8\u3059\u308b\u3053\u3068\u3082\u3001\u30ea\u30fc\u30c0\u30fc\u3092\u9078\u3076\u3053\u3068\u3082\u51fa\u6765\u306a\u304f\u306a\u308b\u304b\u3089\u3067\u3059\u3002<\/p>\n<p>\u305d\u3057\u3066\u3088\u3046\u3084\u304f\u5192\u982d\u306e\u7591\u554f\u306b\u623b\u308b\u308f\u3051\u3067\u3059\u3002<\/p>\n<p>\u30af\u30e9\u30b9\u30bf\u30fc\u5185\u306e\u30ce\u30fc\u30c9\u6570\u304c 2 \u306e\u5834\u5408\u3092\u8003\u3048\u3066\u307f\u307e\u3057\u3087\u3046\u3002\u3053\u306e\u30b1\u30fc\u30b9\u3067\u306f\u904e\u534a\u6570\u306f 2 \u306b\u306a\u308b\u306e\u3067\u30011 \u53f0\u304c\u30af\u30e9\u30c3\u30b7\u30e5\u3059\u308b\u3068\u904e\u534a\u6570\u304c\u6210\u7acb\u3057\u306a\u304f\u306a\u308a\u3001\u30af\u30e9\u30b9\u30bf\u30fc\u306f\u6a5f\u80fd\u3057\u306a\u304f\u306a\u308a\u307e\u3059\u3002<\/p>\n<p><a href=\"https:\/\/github.com\/etcd-io\/etcd\/blob\/master\/Documentation\/faq.md#what-is-failure-tolerance\">etcd \u306e FAQ<\/a> \u4e0a\u306b\u63b2\u8f09\u3055\u308c\u3066\u3044\u308b\u8868\u304c\u308f\u304b\u308a\u3084\u3059\u3044\u306e\u3067\u8ee2\u8a18\u3057\u307e\u3059\u3002<\/p>\n<table>\n<thead>\n<tr>\n<th align=\"center\">Cluster Size<\/th>\n<th align=\"center\">Majority<\/th>\n<th align=\"center\">Failure Tolerance<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td align=\"center\">1<\/td>\n<td align=\"center\">1<\/td>\n<td align=\"center\">0<\/td>\n<\/tr>\n<tr>\n<td align=\"center\">2<\/td>\n<td align=\"center\">2<\/td>\n<td align=\"center\">0<\/td>\n<\/tr>\n<tr>\n<td align=\"center\">3<\/td>\n<td align=\"center\">2<\/td>\n<td align=\"center\">1<\/td>\n<\/tr>\n<tr>\n<td align=\"center\">4<\/td>\n<td align=\"center\">3<\/td>\n<td align=\"center\">1<\/td>\n<\/tr>\n<tr>\n<td align=\"center\">5<\/td>\n<td align=\"center\">3<\/td>\n<td align=\"center\">2<\/td>\n<\/tr>\n<tr>\n<td align=\"center\">6<\/td>\n<td align=\"center\">4<\/td>\n<td align=\"center\">2<\/td>\n<\/tr>\n<tr>\n<td align=\"center\">7<\/td>\n<td align=\"center\">4<\/td>\n<td align=\"center\">3<\/td>\n<\/tr>\n<tr>\n<td align=\"center\">8<\/td>\n<td align=\"center\">5<\/td>\n<td align=\"center\">3<\/td>\n<\/tr>\n<tr>\n<td align=\"center\">9<\/td>\n<td align=\"center\">5<\/td>\n<td align=\"center\">4<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u8868\u5185\u306e <strong>Cluster Size<\/strong> \u306f\u30af\u30e9\u30b9\u30bf\u30fc\u5185\u306e\u5168\u30ce\u30fc\u30c9\u6570\u3001<strong>Majority<\/strong> \u306f\u904e\u534a\u6570\u3068\u306a\u308b\u30ce\u30fc\u30c9\u6570\u3001<strong>Failure Tolerance<\/strong> \u306f\u4f55\u53f0\u306e\u30ce\u30fc\u30c9\u306e\u6545\u969c\u306b\u307e\u3067\u8010\u3048\u3089\u308c\u308b\u304b\u3092\u8868\u3057\u3066\u3044\u307e\u3059\u3002<\/p>\n<p>Failure Tolerance \u3092\u898b\u308c\u3070\u660e\u3089\u304b\u3067\u3059\u304c\u3001Cluster Size \u304c 3 \u4ee5\u4e0a\u3067\u306a\u3051\u308c\u3070\u3001Failure Tolerance \u304c 0 \u3068\u306a\u3063\u3066\u3057\u307e\u3044\u307e\u3059\u3002\u3053\u308c\u304c\u3001\"three\" \u306e\u7406\u7531\u3067\u3057\u305f\u3002<\/p>\n<p>\u307e\u305f\u3001\u8868\u304b\u3089\u306f\u3001Cluster Size \u304c\u5947\u6570\u306b\u306a\u308b\u3088\u3046\u306b\u30ce\u30fc\u30c9\u3092\u8ffd\u52a0\u3057\u306a\u3051\u308c\u3070\u3001Failure Tolerance \u306b\u5f71\u97ff\u3092\u4e0e\u3048\u306a\u3044\u3053\u3068\u3082\u898b\u3066\u53d6\u308c\u307e\u3059\u3002<\/p>\n<p>\u3053\u306e\u3088\u3046\u306b\u3057\u3066\u3001etcd \u306e HA \u69cb\u6210\u306f<strong>\u8010\u969c\u5bb3\u6027\uff08fault tolerance\uff09<\/strong>\u3092\u5411\u4e0a\u3055\u305b\u3066\u3044\u307e\u3059\u3002<\/p>\n<h2>\u6700\u5f8c\u306b<\/h2>\n<p>\u4eca\u56de\u306e\u8a18\u4e8b\u3067\u306f Raft \u306e log compaction \u306e\u4ed5\u7d44\u307f\u3084\u3001membership changes \u306b\u3064\u3044\u3066\u89e6\u308c\u307e\u305b\u3093\u3067\u3057\u305f\u3002leader election \u3084 log replication \u3082\u542b\u3081\u3001Raft \u306e\u8a73\u7d30\u306f\u4e0b\u8a18\u8ad6\u6587\u306b\u308f\u304b\u308a\u3084\u3059\u304f\u8aac\u660e\u3055\u308c\u3066\u3044\u307e\u3059\u306e\u3067\u3001\u8208\u5473\u304c\u3042\u308b\u65b9\u306f\u3053\u3061\u3089\u3092\u3054\u53c2\u8003\u304f\u3060\u3055\u3044\u3002<\/p>\n<ul>\n<li><a href=\"https:\/\/ramcloud.stanford.edu\/raft.pdf\">In Search of an Understandable Consensus Algorithm (Extended Version) | Diego Ongaro and John Ousterhout | Stanford University<\/a><\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>\u3053\u3093\u306b\u3061\u306f\u3002\u677e\u672c\u3067\u3059\u3002<\/p>\n<p>Kubernetes \u30b3\u30f3\u30c8\u30ed\u30fc\u30eb\u30d7\u30ec\u30fc\u30f3\u306e HA(High Available) \u69cb\u6210\u306f\u4e8c\u901a\u308a\u3042\u308a\u307e\u3059\u304c\u3001\u516c\u5f0f\u30c9\u30ad\u30e5\u30e1\u30f3\u30c8\u5185\u306b\u6b21\u306e\u3088\u3046\u306a\u8a18\u8ff0\u304c\u3042\u308a\u3001\u3044\u305a\u308c\u306e\u65b9\u5f0f\u3067\u3082 3 \u53f0\u4ee5\u4e0a\u306e\u30de\u30b7\u30f3\u3067\u30af\u30e9\u30b9\u30bf\u30fc\u3092\u69cb\u6210\u3059\u308b\u3053\u3068\u304c\u6c42\u3081\u3089\u308c\u3066\u3044\u307e\u3059\u3002<br \/><a href=\"https:\/\/www.techscore.com\/blog\/2019\/03\/28\/raft-consensus-algorithm\/\">\u7d9a\u304d\u3092\u8aad\u3080...<\/a><\/p>\n","protected":false},"author":14,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[18],"tags":[309,240],"_links":{"self":[{"href":"https:\/\/www.techscore.com\/blog\/wp-json\/wp\/v2\/posts\/22190"}],"collection":[{"href":"https:\/\/www.techscore.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.techscore.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.techscore.com\/blog\/wp-json\/wp\/v2\/users\/14"}],"replies":[{"embeddable":true,"href":"https:\/\/www.techscore.com\/blog\/wp-json\/wp\/v2\/comments?post=22190"}],"version-history":[{"count":92,"href":"https:\/\/www.techscore.com\/blog\/wp-json\/wp\/v2\/posts\/22190\/revisions"}],"predecessor-version":[{"id":22423,"href":"https:\/\/www.techscore.com\/blog\/wp-json\/wp\/v2\/posts\/22190\/revisions\/22423"}],"wp:attachment":[{"href":"https:\/\/www.techscore.com\/blog\/wp-json\/wp\/v2\/media?parent=22190"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.techscore.com\/blog\/wp-json\/wp\/v2\/categories?post=22190"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.techscore.com\/blog\/wp-json\/wp\/v2\/tags?post=22190"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}