1，报错too many open files

• 设置ulimit
• open files默认为1024

# ulimit -a
core file size          (blocks, -c) 0
data seg size           (kbytes, -d) unlimited
scheduling priority             (-e) 0
file size               (blocks, -f) unlimited
pending signals                 (-i) 514927
max locked memory       (kbytes, -l) 16384
max memory size         (kbytes, -m) unlimited
open files                      (-n) 1024
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size              (kbytes, -s) 8192
cpu time               (seconds, -t) unlimited
max user processes              (-u) 514927
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited

2，修改open files

• vim /etc/security/limits.conf添加

* soft     nproc          65535
* hard     nproc          65535
* soft     nofile         65535
* hard     nofile         65535

root soft     nproc          65535
root hard     nproc          65535
root soft     nofile         65535
root hard     nofile         65535

bro soft     nproc          65535
bro hard     nproc          65535
bro soft     nofile         65535
bro hard     nofile         65535

• vim /etc/pam.d/common-session添加

session required pam_limits.so

• vim /etc/pam.d/common-session-noninteractive添加

session required pam_limits.so

• vim /etc/systemd/system.conf修改

DefaultLimitNOFILE=65535

• 重启
• 修改成功open files 65535

# ulimit -a
core file size          (blocks, -c) 0
data seg size           (kbytes, -d) unlimited
scheduling priority             (-e) 0
file size               (blocks, -f) unlimited
pending signals                 (-i) 514927
max locked memory       (kbytes, -l) 16384
max memory size         (kbytes, -m) unlimited
open files                      (-n) 65535
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size              (kbytes, -s) 8192
cpu time               (seconds, -t) unlimited
max user processes              (-u) 65535
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited

• 8565为进程，查看Max open files

# cat /proc/8565/limits
Limit                     Soft Limit           Hard Limit           Units
Max cpu time              unlimited            unlimited            seconds
Max file size             unlimited            unlimited            bytes
Max data size             unlimited            unlimited            bytes
Max stack size            8388608              unlimited            bytes
Max core file size        0                    unlimited            bytes
Max resident set          unlimited            unlimited            bytes
Max processes             65535                65535                processes
Max open files            65535                65535                files
Max locked memory         16777216             16777216             bytes
Max address space         unlimited            unlimited            bytes
Max file locks            unlimited            unlimited            locks
Max pending signals       514927               514927               signals
Max msgqueue size         819200               819200               bytes
Max nice priority         0                    0
Max realtime priority     0                    0
Max realtime timeout      unlimited            unlimited            us

3，通过设置环境变量修改

• vim /etc/profile 增加

ulimit -n 65535

# ulimit -n
65535

4，pen files修改为1048576

# cat /proc/sys/fs/file-max
19768128

# cat /proc/sys/fs/nr_open
1048576

• 当前值 hard 值

ulimit -a

# ulimit -Sa | grep -ni "open"
8:open files                      (-n) 1024

# ulimit -Ha | grep -ni "open"
8:open files                      (-n) 1048576

5，永久修改 ulimit

# ulimit -a | grep -ni "open"
8:open files                      (-n) 1024
# ulimit -Sa | grep -ni "open"
8:open files                      (-n) 1024
# ulimit -Ha | grep -ni "open"
8:open files                      (-n) 1048576

• 修改

# vim /etc/systemd/user.conf
#DefaultLimitNOFILE=
DefaultLimitNOFILE=1048576

# vim /etc/systemd/system.conf
#DefaultLimitNOFILE=
DefaultLimitNOFILE=1048576

vim /etc/security/limits.conf

• 添加

* soft     nproc          1048576
* hard     nproc          1048576
* soft     nofile         1048576
* hard     nofile         1048576

root soft     nproc          1048576
root hard     nproc          1048576
root soft     nofile         1048576
root hard     nofile         1048576

bro soft     nproc          1048576
bro hard     nproc          1048576
bro soft     nofile         1048576
bro hard     nofile         1048576

reboot

# ulimit -a | grep -ni "open"
8:open files                      (-n) 1048576
# ulimit -Sa | grep -ni "open"
8:open files                      (-n) 1048576

参考：

1. Ubuntu 设置 ulimit
2. How to increase max open files limit on Ubuntu 18.04?
3. 修改linux 最大文件限制数 ulimit
4. linux 系统下open-file文件数限制修改
5. ulimit 资源限制无效
6. linux - Openfire进程未遵循limits.conf中的ulimit nofiles值
7. Filecoin 资源分享 Ulimit 问题
8. 修改 ulimit