[Unit]
Description=ElasticSearch: Distributed and RESTful search engine
Documentation=https://elastic.co
After=network.target

[Service]
Type=simple
User=__APP__
Group=__APP__
RuntimeDirectory=__APP__
Environment="ES_JAVA_HOME=__INSTALL_DIR__/jdk"
Environment="ES_PATH_CONF=__INSTALL_DIR__/config"
Environment="PID_DIR=/run/__APP__"
Environment="ES_SD_NOTIFY=true"
WorkingDirectory=__INSTALL_DIR__/
ExecStart=__INSTALL_DIR__/bin/elasticsearch -p ${PID_DIR}/__APP__.pid --quiet
StandardOutput=append:/var/log/__APP__/__APP__.log
StandardError=inherit

# Specifies the maximum file descriptor number that can be opened by this process
LimitNOFILE=65535

# 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=900

# Sandboxing options to harden security
# Depending on specificities of your service/app, you may need to tweak these
# .. but this should be a good baseline
# Details for these options: https://www.freedesktop.org/software/systemd/man/systemd.exec.html
NoNewPrivileges=yes
PrivateTmp=yes
PrivateDevices=yes
RestrictAddressFamilies=AF_UNIX AF_INET AF_INET6 AF_NETLINK
RestrictNamespaces=yes
RestrictRealtime=yes
DevicePolicy=closed
ProtectClock=yes
ProtectHostname=yes
ProtectProc=invisible
ProtectSystem=full
ProtectControlGroups=yes
ProtectKernelModules=yes
ProtectKernelTunables=yes
LockPersonality=yes
SystemCallArchitectures=native
SystemCallFilter=~@clock @debug @module @mount @obsolete @reboot @setuid @swap @cpu-emulation @privileged

# Denying access to capabilities that should not be relevant for webapps
# Doc: https://man7.org/linux/man-pages/man7/capabilities.7.html
CapabilityBoundingSet=~CAP_RAWIO CAP_MKNOD
CapabilityBoundingSet=~CAP_AUDIT_CONTROL CAP_AUDIT_READ CAP_AUDIT_WRITE
CapabilityBoundingSet=~CAP_SYS_BOOT CAP_SYS_TIME CAP_SYS_MODULE CAP_SYS_PACCT
CapabilityBoundingSet=~CAP_LEASE CAP_LINUX_IMMUTABLE CAP_IPC_LOCK
CapabilityBoundingSet=~CAP_BLOCK_SUSPEND CAP_WAKE_ALARM
CapabilityBoundingSet=~CAP_SYS_TTY_CONFIG
CapabilityBoundingSet=~CAP_MAC_ADMIN CAP_MAC_OVERRIDE
CapabilityBoundingSet=~CAP_NET_ADMIN CAP_NET_BROADCAST CAP_NET_RAW
CapabilityBoundingSet=~CAP_SYS_ADMIN CAP_SYS_PTRACE CAP_SYSLOG

[Install]
WantedBy=multi-user.target