我有一个 elasticsearch，我想将进程设置NOFILE为unlimited。
prlimit --nofile=430000:430000 --pid 3359088成功了，我可以看到它在 中发生了变化/proc/3359088/limits，但是prlimit --nofile=unlimited:unlimited --pid 3359088失败了：
root@elasticsearch:/proc/3359088# sudo prlimit --nofile=unlimited --pid 3359088
prlimit: failed to set the NOFILE resource limit: Operation not permitted
这是它的 systemd 服务文件：
[Unit]
Description=Elasticsearch
Documentation=https://www.elastic.co
Wants=network-online.target
After=network-online.target
[Service]
Type=notify
RuntimeDirectory=elasticsearch
PrivateTmp=true
Environment=ES_HOME=/usr/share/elasticsearch
Environment=ES_PATH_CONF=/etc/elasticsearch
Environment=PID_DIR=/var/run/elasticsearch
Environment=ES_SD_NOTIFY=true
EnvironmentFile=-/etc/default/elasticsearch
WorkingDirectory=/usr/share/elasticsearch
User=elasticsearch
Group=elasticsearch
ExecStart=/usr/share/elasticsearch/bin/systemd-entrypoint -p ${PID_DIR}/elasticsearch.pid --quiet
# StandardOutput is configured to redirect to journalctl since
# some error messages may be logged in standard output before
# elasticsearch logging system is initialized. Elasticsearch
# stores its logs in /var/log/elasticsearch and does not use
# journalctl by default. If you also want to enable journalctl
# logging, you can simply remove the "quiet" option from ExecStart.
StandardOutput=journal
StandardError=inherit
# Specifies the maximum file descriptor number that can be opened by this process
LimitNOFILE=420000
# Specifies the maximum number of processes
LimitNPROC=4096
# Specifies the maximum size of virtual memory
LimitAS=infinity
# Specifies the maximum file size
LimitFSIZE=infinity
# Disable timeout logic and wait until process is stopped
TimeoutStopSec=0
# SIGTERM signal is used to stop the Java process
KillSignal=SIGTERM
# Send the signal only to the JVM rather than its control group
KillMode=process
# Java process is never killed
SendSIGKILL=no
# When a JVM receives a SIGTERM signal it exits with code 143
SuccessExitStatus=143
# Allow a slow startup before the systemd notifier module kicks in to extend the timeout
TimeoutStartSec=75
[Install]
WantedBy=multi-user.target
# Built for packages-7.17.5 (packages)
我的操作系统是：Ubuntu 20.04.1 LTS内核版本是5.4.0-122-generic