オープンファイル数の上限を上げる

[J-ogawa]

目的：nginxのworker_connectionsを増やしたい

os側

# /etc/security/limits.conf
#
#This file sets the resource limits for the users logged in via PAM.
#It does not affect resource limits of the system services.
#
#Also note that configuration files in /etc/security/limits.d directory,
#which are read in alphabetical order, override the settings in this
#file in case the domain is the same or more specific.
#That means for example that setting a limit for wildcard domain here
#can be overriden with a wildcard setting in a config file in the
#subdirectory, but a user specific setting here can be overriden only
#with a user specific setting in the subdirectory.
#
#Each line describes a limit for a user in the form:
#
#<domain>        <type>  <item>  <value>
#
#Where:
#<domain> can be:
#        - a user name
#        - a group name, with @channel syntax
#        - the wildcard *, for default entry
#        - the wildcard %, can be also used with %group syntax,
#                 for maxlogin limit
#
#<type> can have the two values:
#        - "soft" for enforcing the soft limits
#        - "hard" for enforcing hard limits
#
#<item> can be one of the following:
#        - core - limits the core file size (KB)
#        - data - max data size (KB)
#        - fsize - maximum filesize (KB)
#        - memlock - max locked-in-memory address space (KB)
#        - nofile - max number of open files
#        - rss - max resident set size (KB)
#        - stack - max stack size (KB)
#        - cpu - max CPU time (MIN)
#        - nproc - max number of processes
#        - as - address space limit (KB)
#        - maxlogins - max number of logins for this user
#        - maxsyslogins - max number of logins on the system
#        - priority - the priority to run user process with
#        - locks - max number of file locks the user can hold
#        - sigpending - max number of pending signals
#        - msgqueue - max memory used by POSIX message queues (bytes)
#        - nice - max nice priority allowed to raise to values: [-20, 19]
#        - rtprio - max realtime priority
#
#<domain>      <type>  <item>         <value>
#

#*               soft    core            0
#*               hard    rss             10000
#@student        hard    nproc           20
#@faculty        soft    nproc           20
#@faculty        hard    nproc           50
#ftp             hard    nproc           0
#@student        -       maxlogins       4
*                -       nofile          32768                  # <- これを追加する

[J-ogawa]

nginx側 worker_connectionsを増やすことが可能 ファイルディスクリプタの上限数 > worker_connections * worker_process ? worker_rlimit_nofileはworker_connectionsの4倍くらいがいいと言う人もいればデカい数を入れている人もいる

https://qiita.com/toshihirock/items/f3aac142882c9c320b7f

[hamadu]

ちょっと違う話だけどISUCON4リトライしたら「（ローカルの）ポートの空きがない」罠に引っかかって、これは /etc/sysctl.conf に

net.ipv4.ip_local_port_range = 10000 65000
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_fin_timeout = 10

を追記で回避できた