{"id":7660,"date":"2026-08-17T10:12:17","date_gmt":"2026-08-17T02:12:17","guid":{"rendered":"https:\/\/i007.cc\/wordpress\/?p=7660"},"modified":"2026-08-17T10:12:17","modified_gmt":"2026-08-17T02:12:17","slug":"etcd-%e5%8e%9f%e7%90%86","status":"publish","type":"post","link":"https:\/\/i007.cc\/wordpress\/archives\/7660","title":{"rendered":"ETCD \u539f\u7406"},"content":{"rendered":"

etcd \u662f\u4e00\u4e2a\u57fa\u4e8e Raft \u4e00\u81f4\u6027\u7b97\u6cd5<\/strong>\u5b9e\u73b0\u7684\u5206\u5e03\u5f0f\u3001\u5f3a\u4e00\u81f4\u6027 key-value \u5b58\u50a8\u7cfb\u7edf,\u4e13\u95e8\u4e3a\u5b58\u50a8\u5206\u5e03\u5f0f\u7cfb\u7edf\u91cc\u6700\u5173\u952e\u7684\u5143\u6570\u636e\u8bbe\u8ba1\uff08\u6bd4\u5982\u914d\u7f6e\u4fe1\u606f\u3001\u670d\u52a1\u53d1\u73b0\u6570\u636e\u3001\u5206\u5e03\u5f0f\u9501),\u6700\u5178\u578b\u7684\u5e94\u7528\u5c31\u662f Kubernetes \u7528\u5b83\u5b58\u50a8\u6574\u4e2a\u96c6\u7fa4\u7684\u6240\u6709\u72b6\u6001\u6570\u636e\u3002\u5b83\u7684\u8bbe\u8ba1\u76ee\u6807\u548c Redis \u5b8c\u5168\u4e0d\u540c:Redis \u8ffd\u6c42\u6781\u81f4\u6027\u80fd\u3001\u53ef\u4ee5\u5bb9\u5fcd\u6700\u7ec8\u4e00\u81f4\uff08\u5f02\u6b65\u590d\u5236),\u800c etcd \u8ffd\u6c42\u7684\u662f\u5f3a\u4e00\u81f4\u6027\u548c\u9ad8\u53ef\u9760,\u5b81\u53ef\u727a\u7272\u4e00\u4e9b\u6027\u80fd\u4e5f\u8981\u4fdd\u8bc1\u6570\u636e\u4e0d\u4e22\u3001\u4e0d\u810f\u8bfb\u3002<\/p>\n

\u6838\u5fc3:Raft \u4e00\u81f4\u6027\u7b97\u6cd5<\/h3>\n

etcd \u96c6\u7fa4\u901a\u5e38\u7531\u5947\u6570\u4e2a\u8282\u70b9\u7ec4\u6210\uff08\u63a8\u8350 3 \u6216 5 \u4e2a,\u65b9\u4fbf\u8ba1\u7b97\u591a\u6570\u6d3e\uff09,\u8282\u70b9\u4e4b\u95f4\u901a\u8fc7 Raft \u534f\u8bae\u4fdd\u8bc1\u6240\u6709\u8282\u70b9\u7684\u6570\u636e\u6700\u7ec8\u4e00\u81f4\u3002Raft \u628a\u95ee\u9898\u62c6\u6210\u4e09\u4e2a\u5b50\u95ee\u9898\u6765\u89e3\u51b3\u3002<\/p>\n

Leader \u9009\u4e3e\u65b9\u9762,\u96c6\u7fa4\u91cc\u4efb\u610f\u65f6\u523b\u53ea\u6709\u4e00\u4e2a Leader,\u5176\u4f59\u662f Follower\u3002\u8282\u70b9\u6709\u9009\u4e3e\u8d85\u65f6\u65f6\u95f4,\u5982\u679c Follower \u5728\u8d85\u65f6\u65f6\u95f4\u5185\u6ca1\u6536\u5230 Leader \u7684\u5fc3\u8df3,\u5c31\u4f1a\u53d8\u6210 Candidate \u53d1\u8d77\u9009\u4e3e,\u7ed9\u81ea\u5df1\u6295\u7968\u5e76\u5411\u5176\u4ed6\u8282\u70b9\u62c9\u7968,\u62ff\u5230\u591a\u6570\u7968\uff08\u8d85\u8fc7\u534a\u6570\u8282\u70b9)\u7684\u6210\u4e3a\u65b0 Leader\u3002\u8fd9\u4e2a\u673a\u5236\u4fdd\u8bc1\u4e86\u4efb\u4f55\u65f6\u5019\u96c6\u7fa4\u53ea\u6709\u4e00\u4e2a”\u6743\u5a01\u5199\u5165\u70b9”,\u4e0d\u4f1a\u51fa\u73b0\u8111\u88c2\u65f6\u4e24\u8fb9\u90fd\u80fd\u5199\u7684\u60c5\u51b5\uff08\u56e0\u4e3a\u62ff\u4e0d\u5230\u591a\u6570\u7968\u5c31\u9009\u4e0d\u51fa Leader\uff09\u3002<\/p>\n

\u65e5\u5fd7\u590d\u5236\u65b9\u9762,\u6240\u6709\u5199\u8bf7\u6c42\u90fd\u5fc5\u987b\u5148\u53d1\u7ed9 Leader,Leader \u628a\u8fd9\u6761\u53d8\u66f4\u4f5c\u4e3a\u4e00\u6761\u65e5\u5fd7(entry)\u8ffd\u52a0\u5230\u81ea\u5df1\u7684\u65e5\u5fd7\u91cc,\u7136\u540e\u5e76\u884c\u53d1\u7ed9\u6240\u6709 Follower,\u5f53\u591a\u6570\u8282\u70b9<\/strong>\uff08\u4e0d\u662f\u5168\u90e8)\u90fd\u786e\u8ba4\u5199\u5165\u6210\u529f\u540e,\u8fd9\u6761\u65e5\u5fd7\u624d\u7b97”\u5df2\u63d0\u4ea4\uff08committed\uff09”,Leader \u624d\u4f1a\u771f\u6b63\u5e94\u7528\u5230\u72b6\u6001\u673a\u5e76\u8fd4\u56de\u5ba2\u6237\u7aef\u6210\u529f\u3002\u8fd9\u91cc\u7684\u5173\u952e\u8bbe\u8ba1\u662f”\u591a\u6570\u6d3e\u786e\u8ba4”\u800c\u4e0d\u662f”\u5168\u90e8\u786e\u8ba4”,\u8fd9\u6837\u5373\u4f7f\u5c11\u6570\u8282\u70b9\uff08\u6bd4\u5982 5 \u8282\u70b9\u91cc\u7684 2 \u4e2a)\u6302\u6389\u6216\u8005\u7f51\u7edc\u5206\u533a,\u96c6\u7fa4\u4f9d\u7136\u80fd\u6b63\u5e38\u5199\u5165,\u4e0d\u4f1a\u56e0\u4e3a\u4e2a\u522b\u8282\u70b9\u6545\u969c\u5c31\u6574\u4f53\u4e0d\u53ef\u7528,\u8fd9\u4e5f\u662f etcd \u96c6\u7fa4\u901a\u5e38\u914d\u7f6e\u5947\u6570\u8282\u70b9\u3001\u4e14\u80fd\u5bb9\u5fcd (n-1)\/2<\/code> \u4e2a\u8282\u70b9\u6545\u969c\u7684\u539f\u56e0\u3002<\/p>\n

\u5b89\u5168\u6027\u65b9\u9762,Raft \u8fd8\u6709\u4e00\u5957\u89c4\u5219\u4fdd\u8bc1\u5df2\u7ecf\u63d0\u4ea4\u7684\u65e5\u5fd7\u4e0d\u4f1a\u4e22\u5931\u3001\u4e0d\u4f1a\u88ab\u8986\u76d6,\u6bd4\u5982\u9009\u4e3e\u65f6\u5019\u9009\u4eba\u7684\u65e5\u5fd7\u5fc5\u987b”\u8db3\u591f\u65b0”\uff08term \u66f4\u5927\u6216\u8005\u65e5\u5fd7\u66f4\u957f)\u624d\u6709\u8d44\u683c\u5f53\u9009,\u9632\u6b62\u4e00\u4e2a\u65e5\u5fd7\u843d\u540e\u7684\u8282\u70b9\u5f53\u4e0a Leader \u540e\u8986\u76d6\u6389\u5df2\u63d0\u4ea4\u7684\u6570\u636e\u3002<\/p>\n

\u6570\u636e\u6a21\u578b:MVCC<\/h3>\n

etcd \u7684\u6570\u636e\u6a21\u578b\u4e0d\u662f\u7b80\u5355\u7684”key \u8986\u76d6 value”,\u800c\u662f MVCC\uff08\u591a\u7248\u672c\u5e76\u53d1\u63a7\u5236\uff09<\/strong>:\u6bcf\u6b21\u5199\u5165\uff08\u589e\u3001\u6539\u3001\u5220)\u90fd\u4f1a\u751f\u6210\u4e00\u4e2a\u5168\u5c40\u9012\u589e\u7684\u7248\u672c\u53f7\uff08revision),\u65e7\u7248\u672c\u7684\u6570\u636e\u4e0d\u4f1a\u88ab\u7acb\u5373\u62b9\u6389,\u800c\u662f\u88ab\u4fdd\u7559\u4e0b\u6765\u3002\u8fd9\u5e26\u6765\u4e24\u4e2a\u76f4\u63a5\u597d\u5904:\u4e00\u662f\u53ef\u4ee5\u652f\u6301”\u67e5\u8be2\u67d0\u4e2a\u5386\u53f2\u7248\u672c\u7684\u6570\u636e\u662f\u4ec0\u4e48\u6837”,\u4e8c\u662f\u5929\u7136\u652f\u6491\u4e86\u540e\u9762\u8981\u8bb2\u7684 Watch \u673a\u5236,\u53ef\u4ee5\u4ece\u4efb\u610f\u4e00\u4e2a revision \u5f00\u59cb\u8ba2\u9605\u4e4b\u540e\u53d1\u751f\u7684\u6240\u6709\u53d8\u66f4,\u4e0d\u4f1a\u6f0f\u4e8b\u4ef6\u3002<\/p>\n

etcd \u5185\u90e8\u7528\u4e00\u68f5\u5185\u5b58\u4e2d\u7684 B-tree(treeIndex)\u7ef4\u62a4 key \u5230\u5404\u7248\u672c revision \u7684\u6620\u5c04\u5173\u7cfb,\u5b9e\u9645\u7684\u7248\u672c\u5316\u6570\u636e\u5219\u6301\u4e45\u5316\u5b58\u50a8\u5728\u78c1\u76d8\u4e0a\u7684 boltdb<\/strong>\uff08\u4e00\u4e2a\u57fa\u4e8e B+ \u6811\u7684\u5d4c\u5165\u5f0f\u5355\u673a KV \u5b58\u50a8\u5f15\u64ce)\u91cc,\u6bcf\u4e2a revision \u4f5c\u4e3a boltdb \u91cc\u7684 key,\u8fd9\u6837\u8bfb\u53d6\u5386\u53f2\u7248\u672c\u672c\u8d28\u4e0a\u5c31\u662f\u67e5 boltdb \u91cc\u5bf9\u5e94 revision \u7684\u8bb0\u5f55\u3002<\/p>\n

\u6301\u4e45\u5316:WAL + Snapshot<\/h3>\n

\u4e3a\u4e86\u4fdd\u8bc1 Leader \u5d29\u6e83\u91cd\u542f\u540e\u6570\u636e\u4e0d\u4e22,etcd \u5728\u6570\u636e\u771f\u6b63\u843d\u76d8 boltdb \u4e4b\u524d,\u4f1a\u5148\u5199 WAL\uff08Write-Ahead Log,\u9884\u5199\u65e5\u5fd7)<\/strong>,\u6240\u6709\u5199\u64cd\u4f5c\u5148\u987a\u5e8f\u8ffd\u52a0\u5199\u5165 WAL \u6587\u4ef6,\u8fd9\u4e00\u6b65\u662f\u540c\u6b65\u5237\u76d8\u7684,\u53ea\u6709 WAL \u5199\u6210\u529f\u624d\u8ba4\u4e3a\u8fd9\u6761\u65e5\u5fd7\u5b89\u5168\u843d\u5730,\u5373\u4f7f\u8fdb\u7a0b\u5d29\u6e83,\u91cd\u542f\u540e\u4e5f\u80fd\u901a\u8fc7\u91cd\u653e WAL \u6062\u590d\u5230\u5d29\u6e83\u524d\u7684\u72b6\u6001\u3002<\/p>\n

\u4f46 WAL \u662f\u4e00\u76f4\u8ffd\u52a0\u589e\u957f\u7684,\u4e0d\u80fd\u65e0\u9650\u81a8\u80c0,\u6240\u4ee5 etcd \u4f1a\u5b9a\u671f\u505a Snapshot\uff08\u5feb\u7167\uff09<\/strong>:\u628a\u5f53\u524d\u72b6\u6001\u673a\u7684\u5b8c\u6574\u6570\u636e\u6253\u4e00\u4e2a\u5feb\u7167\u843d\u76d8,\u5e76\u628a\u8fd9\u4e2a\u5feb\u7167\u70b9\u4e4b\u524d\u7684 WAL \u65e5\u5fd7\u6e05\u7406\u6389,\u7c7b\u4f3c Redis RDB \u7684\u601d\u8def,\u517c\u987e\u6062\u590d\u901f\u5ea6\u548c\u5b58\u50a8\u7a7a\u95f4\u3002<\/p>\n

Watch \u673a\u5236<\/h3>\n

etcd \u4e00\u4e2a\u5f88\u91cd\u8981\u7684\u80fd\u529b\u662f\u8ba9\u5ba2\u6237\u7aef\u53ef\u4ee5”\u8ba2\u9605\u67d0\u4e2a key \u6216\u67d0\u4e2a\u524d\u7f00\u7684\u53d8\u5316”,\u4e00\u65e6\u53d1\u751f\u53d8\u66f4\u7acb\u523b\u6536\u5230\u901a\u77e5,\u8fd9\u662f Kubernetes \u80fd\u5b9e\u65f6\u611f\u77e5\u96c6\u7fa4\u72b6\u6001\u53d8\u5316\uff08\u6bd4\u5982 Pod \u88ab\u521b\u5efa\/\u5220\u9664)\u7684\u57fa\u7840\u3002Watch \u7684\u5b9e\u73b0\u6b63\u662f\u4f9d\u8d56\u524d\u9762\u8bf4\u7684 MVCC:\u5ba2\u6237\u7aef\u53ef\u4ee5\u6307\u5b9a”\u4ece\u67d0\u4e2a revision \u5f00\u59cb watch”,etcd \u4f1a\u628a\u8fd9\u4e4b\u540e\u53d1\u751f\u7684\u6240\u6709\u53d8\u66f4\u4e8b\u4ef6\u901a\u8fc7 gRPC \u7684\u6d41\u5f0f\u63a5\u53e3\uff08server streaming)\u6301\u7eed\u63a8\u9001\u7ed9\u5ba2\u6237\u7aef,\u4e0d\u4f1a\u56e0\u4e3a\u7f51\u7edc\u6296\u52a8\u65ad\u7ebf\u91cd\u8fde\u5c31\u4e22\u4e8b\u4ef6,\u53ea\u8981\u6309\u4e0a\u6b21\u6536\u5230\u7684 revision \u7ee7\u7eed watch \u5373\u53ef\u7eed\u4e0a\u3002<\/p>\n

Lease \u673a\u5236:\u5b9e\u73b0 TTL \u548c\u5fc3\u8df3<\/h3>\n

etcd \u652f\u6301\u7ed9 key \u7ed1\u5b9a\u4e00\u4e2a Lease\uff08\u79df\u7ea6)<\/strong>,\u79df\u7ea6\u6709 TTL,\u5230\u671f\u5982\u679c\u6ca1\u6709\u7eed\u7ea6\uff08renew\/keepalive),\u7ed1\u5b9a\u7684 key \u4f1a\u88ab\u81ea\u52a8\u5220\u9664\u3002\u8fd9\u4e2a\u673a\u5236\u662f\u5b9e\u73b0\u670d\u52a1\u53d1\u73b0\u548c\u5206\u5e03\u5f0f\u9501\u7684\u57fa\u7840:\u670d\u52a1\u5b9e\u4f8b\u6ce8\u518c\u81ea\u5df1\u7684\u5730\u5740\u5230 etcd \u4e0a\u5e76\u7ed1\u5b9a\u4e00\u4e2a\u79df\u7ea6,\u5b9a\u671f\u53d1\u5fc3\u8df3\u7eed\u7ea6,\u5982\u679c\u670d\u52a1\u6302\u6389\u505c\u6b62\u7eed\u7ea6,\u79df\u7ea6\u5230\u671f,\u5bf9\u5e94\u7684 key \u81ea\u52a8\u88ab\u6e05\u7406,\u5176\u4ed6\u670d\u52a1\u901a\u8fc7 watch \u5c31\u80fd\u611f\u77e5\u5230\u8fd9\u4e2a\u5b9e\u4f8b\u4e0b\u7ebf\u4e86,\u4e0d\u9700\u8981\u989d\u5916\u7684\u5fc3\u8df3\u68c0\u6d4b\u7ec4\u4ef6\u3002<\/p>\n

\u8bfb\u4e00\u81f4\u6027:\u7ebf\u6027\u4e00\u81f4\u8bfb vs \u4e32\u884c\u8bfb<\/h3>\n

etcd \u9ed8\u8ba4\u63d0\u4f9b\u7684\u662f\u7ebf\u6027\u4e00\u81f4\u8bfb\uff08linearizable read\uff09<\/strong>,\u4fdd\u8bc1\u8bfb\u5230\u7684\u6570\u636e\u4e00\u5b9a\u662f\u6700\u65b0\u5df2\u63d0\u4ea4\u7684,\u4e0d\u4f1a\u8bfb\u5230\u8fc7\u671f\u6570\u636e\u3002\u65e9\u671f\u5b9e\u73b0\u662f\u6bcf\u6b21\u8bfb\u90fd\u8981\u8d70\u4e00\u904d Raft \u65e5\u5fd7\u786e\u8ba4\uff08\u6210\u672c\u8f83\u9ad8),\u540e\u6765\u4f18\u5316\u6210 ReadIndex<\/strong> \u673a\u5236:Leader \u5728\u5904\u7406\u8bfb\u8bf7\u6c42\u65f6\u8bb0\u5f55\u5f53\u524d\u7684 commit index,\u53ea\u9700\u8981\u8ddf\u591a\u6570\u8282\u70b9\u786e\u8ba4\u4e00\u6b21\u81ea\u5df1\u4ecd\u7136\u662f\u5408\u6cd5 Leader\uff08\u4e0d\u9700\u8981\u771f\u6b63\u5199\u65e5\u5fd7),\u518d\u7b49\u72b6\u6001\u673a\u5e94\u7528\u5230\u8fd9\u4e2a index,\u5c31\u80fd\u4fdd\u8bc1\u8fd4\u56de\u7684\u6570\u636e\u662f\u6700\u65b0\u7684,\u7701\u6389\u4e86\u4e0d\u5fc5\u8981\u7684\u78c1\u76d8 IO\u3002\u5982\u679c\u5bf9\u4e00\u81f4\u6027\u8981\u6c42\u6ca1\u90a3\u4e48\u9ad8\u3001\u66f4\u770b\u91cd\u6027\u80fd,\u4e5f\u53ef\u4ee5\u7528\u4e32\u884c\u8bfb\uff08serializable read\uff09<\/strong>,\u76f4\u63a5\u8bfb\u672c\u5730\u67d0\u4e2a\u8282\u70b9\u7684\u72b6\u6001\u673a,\u53ef\u80fd\u8bfb\u5230\u7565\u5fae\u843d\u540e\u7684\u6570\u636e,\u4f46\u5ef6\u8fdf\u66f4\u4f4e\u3002<\/p>\n

\u4e00\u53e5\u8bdd\u603b\u7ed3<\/h3>\n

etcd \u7684\u6838\u5fc3\u662f\u7528 Raft \u534f\u8bae\u5728\u591a\u4e2a\u8282\u70b9\u95f4\u5bf9”\u5199\u64cd\u4f5c\u987a\u5e8f”\u8fbe\u6210\u5f3a\u4e00\u81f4\u5171\u8bc6,\u914d\u5408 WAL \u4fdd\u8bc1\u5355\u673a\u6545\u969c\u540e\u6570\u636e\u4e0d\u4e22\u3001Snapshot \u63a7\u5236\u65e5\u5fd7\u589e\u957f\u3001MVCC \u6570\u636e\u6a21\u578b\u5929\u7136\u652f\u6491\u5386\u53f2\u7248\u672c\u67e5\u8be2\u548c Watch \u4e8b\u4ef6\u8ba2\u9605\u3001Lease \u673a\u5236\u63d0\u4f9b TTL \u548c\u5fc3\u8df3\u7eed\u7ea6\u80fd\u529b,\u5171\u540c\u6784\u6210\u4e86\u4e00\u4e2a\u80fd\u88ab Kubernetes \u8fd9\u7c7b\u7cfb\u7edf\u5b89\u5fc3\u62ff\u6765\u5b58\u653e”\u751f\u6b7b\u6538\u5173”\u7684\u5143\u6570\u636e\u7684\u5f3a\u4e00\u81f4\u5b58\u50a8\u3002<\/p>\n

\u5982\u679c\u60f3\u7ee7\u7eed\u6df1\u5165,\u53ef\u4ee5\u804a\u804a etcd \u662f\u600e\u4e48\u5904\u7406\u7f51\u7edc\u5206\u533a\u4e0b\u7684\u8111\u88c2\u95ee\u9898\u7684\u3001boltdb \u7684 B+\u6811\u5b58\u50a8\u7ec6\u8282\u3001etcd \u5728 Kubernetes \u91cc\u5177\u4f53\u662f\u600e\u4e48\u88ab apiserver \u4f7f\u7528\u7684,\u6216\u8005\u5bf9\u6bd4\u4e00\u4e0b etcd\uff08CP)\u548c ZooKeeper \u5728\u8bbe\u8ba1\u53d6\u820d\u4e0a\u7684\u5f02\u540c\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"

etcd \u662f\u4e00\u4e2a\u57fa\u4e8e Raft \u4e00\u81f4\u6027\u7b97<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"colormag_page_container_layout":"default_layout","colormag_page_sidebar_layout":"default_layout","footnotes":""},"categories":[24],"tags":[],"class_list":["post-7660","post","type-post","status-publish","format-standard","hentry","category-value_docs"],"_links":{"self":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/7660","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/comments?post=7660"}],"version-history":[{"count":1,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/7660\/revisions"}],"predecessor-version":[{"id":7661,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/7660\/revisions\/7661"}],"wp:attachment":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/media?parent=7660"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/categories?post=7660"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/tags?post=7660"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}