• 修改Ubuntu对CPU，socket，进程，文件数等的限制

    1、参考链接：

    https://blog.csdn.net/huangchonghai/article/details/120735517

    https://www.cnblogs.com/jest549/p/14697557.html

    ubuntu修改 ulimit -c unlimit - Bigben - 博客园

    解决办法：GLib-ERROR **: Creating pipes for GWakeup: Too many open files_柳鲲鹏的博客-CSDN博客

    步骤1、修改/etc/security/limits.conf文件，我的修改如下

    1. # /etc/security/limits.conf
    2. #
    3. #Each line describes a limit for a user in the form:
    4. #
    5. #            
    6. #
    7. #Where:
    8. # can be:
    9. #        - a user name
    10. #        - a group name, with @group syntax
    11. #        - the wildcard *, for default entry
    12. #        - the wildcard %, can be also used with %group syntax,
    13. #                 for maxlogin limit
    14. #        - NOTE: group and wildcard limits are not applied to root.
    15. #          To apply a limit to the root user,  must be
    16. #          the literal username root.
    17. #
    18. # can have the two values:
    19. #        - "soft" for enforcing the soft limits
    20. #        - "hard" for enforcing hard limits
    21. #
    22. # can be one of the following:
    23. #        - core - limits the core file size (KB)
    24. #        - data - max data size (KB)
    25. #        - fsize - maximum filesize (KB)
    26. #        - memlock - max locked-in-memory address space (KB)
    27. #        - nofile - max number of open files
    28. #        - rss - max resident set size (KB)
    29. #        - stack - max stack size (KB)
    30. #        - cpu - max CPU time (MIN)
    31. #        - nproc - max number of processes
    32. #        - as - address space limit (KB)
    33. #        - maxlogins - max number of logins for this user
    34. #        - maxsyslogins - max number of logins on the system
    35. #        - priority - the priority to run user process with
    36. #        - locks - max number of file locks the user can hold
    37. #        - sigpending - max number of pending signals
    38. #        - msgqueue - max memory used by POSIX message queues (bytes)
    39. #        - nice - max nice priority allowed to raise to values: [-20, 19]
    40. #        - rtprio - max realtime priority
    41. #        - chroot - change root to directory (Debian-specific)
    42. #
    43. #                 
    44. #
    45.  
    46. * hard core unlimited
    47. * soft core unlimited 
    48.  
    49. * hard nofile unlimited
    50. * soft nofile unlimited 
    51.  
    52. * hard stack unlimited
    53. * soft stack unlimited 
    54.  
    55. * hard nproc unlimited
    56. * soft nproc unlimited 
    57.  
    58.  
    59.  
    60. #*               soft    core            0
    61. #root            hard    core            100000
    62. #*               hard    rss             10000
    63. #@student        hard    nproc           20
    64. #@faculty        soft    nproc           20
    65. #@faculty        hard    nproc           50
    66. #ftp             hard    nproc           0
    67. #ftp             -       chroot          /ftp
    68. #@student        -       maxlogins       4
    69.  
    70. # End of file
    71. #
    72. #
    73. zrd hard core unlimited
    74. zrd soft core unlimited

    步骤2、修改/etc/pam.d/su 、/etc/pam.d/common-session、/etc/pam.d/login

    关于《limits.conf 生效,与pam_limits.so 文件》，请参考：limits.conf 生效,与pam_limits.so 文件 - 陳聽溪 - 博客园

    步骤3、修改/etc/sysctl.conf文件，在文件中(清除文件原始内容（或者在原有的基础上添加，我是这么干的）)添加如下行（修改网络内核对TCP连接的有关限制）。

    1. #
    2. # /etc/sysctl.conf - Configuration file for setting system variables
    3. # See /etc/sysctl.d/ for additional system variables.
    4. # See sysctl.conf (5) for information.
    5. #
    6.  
    7. #kernel.domainname = example.com
    8.  
    9. # Uncomment the following to stop low-level messages on console
    10. #kernel.printk = 3 4 1 3
    11.  
    12. ##############################################################3
    13. # Functions previously found in netbase
    14. #
    15.  
    16. # Uncomment the next two lines to enable Spoof protection (reverse-path filter)
    17. # Turn on Source Address Verification in all interfaces to
    18. # prevent some spoofing attacks
    19. #net.ipv4.conf.default.rp_filter=1
    20. #net.ipv4.conf.all.rp_filter=1
    21.  
    22. # Uncomment the next line to enable TCP/IP SYN cookies
    23. # See http://lwn.net/Articles/277146/
    24. # Note: This may impact IPv6 TCP sessions too
    25. #net.ipv4.tcp_syncookies=1
    26.  
    27. # Uncomment the next line to enable packet forwarding for IPv4
    28. #net.ipv4.ip_forward=1
    29.  
    30. # Uncomment the next line to enable packet forwarding for IPv6
    31. #  Enabling this option disables Stateless Address Autoconfiguration
    32. #  based on Router Advertisements for this host
    33. #net.ipv6.conf.all.forwarding=1
    34.  
    35.  
    36. ###################################################################
    37. # Additional settings - these settings can improve the network
    38. # security of the host and prevent against some network attacks
    39. # including spoofing attacks and man in the middle attacks through
    40. # redirection. Some network environments, however, require that these
    41. # settings are disabled so review and enable them as needed.
    42. #
    43. # Do not accept ICMP redirects (prevent MITM attacks)
    44. #net.ipv4.conf.all.accept_redirects = 0
    45. #net.ipv6.conf.all.accept_redirects = 0
    46. # _or_
    47. # Accept ICMP redirects only for gateways listed in our default
    48. # gateway list (enabled by default)
    49. # net.ipv4.conf.all.secure_redirects = 1
    50. #
    51. # Do not send ICMP redirects (we are not a router)
    52. #net.ipv4.conf.all.send_redirects = 0
    53. #
    54. # Do not accept IP source route packets (we are not a router)
    55. #net.ipv4.conf.all.accept_source_route = 0
    56. #net.ipv6.conf.all.accept_source_route = 0
    57. #
    58. # Log Martian Packets
    59. #net.ipv4.conf.all.log_martians = 1
    60. #
    61.  
    62. ###################################################################
    63. # Magic system request Key
    64. # 0=disable, 1=enable all
    65. # Debian kernels have this set to 0 (disable the key)
    66. # See https://www.kernel.org/doc/Documentation/sysrq.txt
    67. # for what other values do
    68. #kernel.sysrq=1
    69.  
    70. ###################################################################
    71. # Protected links
    72. #
    73. # Protects against creating or following links under certain conditions
    74. # Debian kernels have both set to 1 (restricted) 
    75. # See https://www.kernel.org/doc/Documentation/sysctl/fs.txt
    76. #fs.protected_hardlinks=0
    77. #fs.protected_symlinks=0
    78.  
    79. ###################xiaogongwei###################
    80.  
    81. net.ipv4.ip_local_port_range = 1024 65535
    82. net.core.rmem_max=16777216
    83. net.core.wmem_max=16777216
    84. net.ipv4.tcp_rmem=4096 87380 16777216
    85. net.ipv4.tcp_wmem=4096 65536 16777216
    86. net.ipv4.tcp_fin_timeout = 10
    87. net.ipv4.tcp_timestamps = 0
    88. net.ipv4.tcp_window_scaling = 0
    89. net.ipv4.tcp_sack = 0
    90. net.core.netdev_max_backlog = 30000
    91. net.ipv4.tcp_no_metrics_save=1
    92. net.core.somaxconn = 262144
    93. net.ipv4.tcp_syncookies = 0
    94. net.ipv4.tcp_max_orphans = 262144
    95. net.ipv4.tcp_max_syn_backlog = 262144
    96. net.ipv4.tcp_synack_retries = 2
    97. net.ipv4.tcp_syn_retries = 2

    步骤4、 执行如下命令（使上述设置生效）：

    1. /sbin/sysctl -p /etc/sysctl.conf
    2. /sbin/sysctl -w net.ipv4.route.flush=1

    步骤5、执行如下命令（linux系统优化完网络必须调高系统允许打开的文件数才能支持大的并发，默认1024是远远不够的）：

    1. echo "ulimit -HSn 65535" >> /etc/rc.local
    2. echo "ulimit -HSn 65535" >>/root/.bash_profile
    3. echo "ulimit -SHn 65535" >> /etc/profile
    4. ulimit -SHn 65535

    步骤6、重启机器

    通过修改，tcp可以达到65535个连接完全没有问题

    通过这个命令 ulimit -n 可以看到值改为65535了，也就是说现在最多支持65536个tcp socket连接了查看当前有多少个TCP连接到当前服务器命令:netstat -antp |grep -i est |wc -l

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  • 原文地址：https://blog.csdn.net/xiaoxiao133/article/details/126575931