NFS 服务器处于活动状态（已退出）

Question

为什么我的 NFS 服务器卡在活动（退出）状态？这是状态：

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    $ sudo systemctl status nfs-server.service\n\xe2\x97\x8f nfs-server.service - NFS server and services\n     Loaded: loaded (/lib/systemd/system/nfs-server.service; enabled; vendor preset: enabled)\n    Drop-In: /run/systemd/generator/nfs-server.service.d\n             \xe2\x94\x94\xe2\x94\x80order-with-mounts.conf\n     Active: active (exited) since Fri 2021-02-19 12:48:48 CET; 7s ago\n    Process: 6257 ExecStartPre=/usr/sbin/exportfs -r (code=exited, status=0/SUCCESS)\n    Process: 6258 ExecStart=/usr/sbin/rpc.nfsd $RPCNFSDARGS (code=exited, status=0/SUCCESS)\n   Main PID: 6258 (code=exited, status=0/SUCCESS)\n\nFeb 19 12:48:47 xxx_name_xxx systemd[1]: Starting NFS server and services...\nFeb 19 12:48:48 xxx_name_xxx systemd[1]: Finished NFS server and services.\n

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这是 /var/log/syslog 中的日志

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Feb 19 12:50:30 xxx_name_xxx systemd-resolved[681]: Server returned error NXDOMAIN, mitigating potential DNS violation DVE-2018-0001, retrying transaction with reduced feature level UDP.\nFeb 19 12:50:30 xxx_name_xxx systemd-resolved[681]: message repeated 3 times: [ Server returned error NXDOMAIN, mitigating potential DNS violation DVE-2018-0001, retrying transaction with reduced feature level UDP.]\nFeb 19 12:50:30 xxx_name_xxx systemd[1]: Condition check resulted in Kernel Module supporting RPCSEC_GSS being skipped.\nFeb 19 12:50:30 xxx_name_xxx systemd[1]: Starting Preprocess NFS configuration...\nFeb 19 12:50:30 xxx_name_xxx systemd[1]: nfs-config.service: Succeeded.\nFeb 19 12:50:30 xxx_name_xxx systemd[1]: Finished Preprocess NFS configuration.\nFeb 19 12:50:30 xxx_name_xxx systemd[1]: Starting NFSv4 ID-name mapping service...\nFeb 19 12:50:30 xxx_name_xxx systemd[1]: Starting NFS Mount Daemon...\nFeb 19 12:50:30 xxx_name_xxx systemd[1]: Condition check resulted in RPC security service for NFS client and server being skipped.\nFeb 19 12:50:30 xxx_name_xxx systemd[1]: Condition check resulted in RPC security service for NFS server being skipped.\nFeb 19 12:50:30 xxx_name_xxx systemd-resolved[681]: Server returned error NXDOMAIN, mitigating potential DNS violation DVE-2018-0001, retrying transaction with reduced feature level UDP.\nFeb 19 12:50:30 xxx_name_xxx systemd-resolved[681]: Server returned error NXDOMAIN, mitigating potential DNS violation DVE-2018-0001, retrying transaction with reduced feature level UDP.\nFeb 19 12:50:30 xxx_name_xxx rpc.mountd[6304]: Version 1.3.3 starting\nFeb 19 12:50:30 xxx_name_xxx systemd[1]: Started NFSv4 ID-name mapping service.\nFeb 19 12:50:30 xxx_name_xxx systemd[1]: Started NFS Mount Daemon.\nFeb 19 12:50:30 xxx_name_xxx systemd[1]: Starting NFS server and services...\nFeb 19 12:50:31 xxx_name_xxx kernel: [ 6663.675764] NFSD: Using UMH upcall client tracking operations.\nFeb 19 12:50:31 xxx_name_xxx kernel: [ 6663.675771] NFSD: starting 90-second grace period (net f0000098)\nFeb 19 12:50:31 xxx_name_xxx systemd[1]: Finished NFS server and services.\n

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这是 uname -a 的结果：

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Linux xxx_name_xxx 5.8.0-7642-generic #47~1612288990~20.04~b8113e7-Ubuntu SMP Wed Feb 3 02:25:36 UTC 2 x86_64 x86_64 x86_64 GNU/Linux\n

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我已经尝试过这个和这个，并尝试停止 nfs-server.service 和 nfs-client.target 并仅启动服务器，但到目前为止没有任何效果。我发现客户端和服务器之间存在冲突，但我无法相信您的计算机无法同时用作 NFS 服务器和客户端。

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Answer 1

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为什么我的 NFS 服务器卡在活动（退出）状态

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因为NFS服务器驻留在内核中并且没有用户空间进程。

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该程序的唯一工作rpc.nfsd是要求内核启动 NFS 服务器 kthreads \xe2\x80\x93，但这些线程与原始 rpc.nfsd 进程没有任何关联，即使进程退出后也会继续运行。

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所以 systemd .service 的行为是正确的（嗯，这是它能做的最好的事情）。它类似于“启动”iptables 或 nftables，两者都没有用户空间守护进程。

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要检查内核 NFS 服务器是否实际运行，请运行ps axf或 htop 并搜索名为“[nfsd]”的 kthreads。您还可以检查以下位置的信息/proc/fs/nfsd：

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# cat /proc/fs/nfsd/threads\n8\n\n# cat /proc/fs/nfsd/versions\n-2 +3 +4 +4.1 +4.2\n\n$ ps axf\n    PID TTY      STAT   TIME COMMAND\n      2 ?        S      0:00 [kthreadd]\n    917 ?        S      0:00  \\_ [lockd]\n   1310 ?        S      0:01  \\_ [nfsd]\n   1311 ?        S      0:01  \\_ [nfsd]\n   1312 ?        S      0:02  \\_ [nfsd]\n

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