[Unit]
Description=DNS Loadbalancer
Documentation=man:dnsdist(1)
Documentation=https://dnsdist.org
Wants=network-online.target
After=network-online.target time-sync.target

[Service]
ExecStartPre=@bindir@/dnsdist --check-config
# Note: when editing the ExecStart command, keep --supervised and --disable-syslog
ExecStart=@bindir@/dnsdist --supervised --disable-syslog
User=@service_user@
Group=@service_group@
SyslogIdentifier=dnsdist
Type=notify
Restart=on-failure
RestartSec=2
TimeoutStopSec=5
StartLimitInterval=0

# Tuning
TasksMax=8192
LimitNOFILE=16384
# Note: increasing the amount of lockable memory is required to use eBPF support
# LimitMEMLOCK=infinity

# Sandboxing
# Note: adding CAP_SYS_ADMIN (or CAP_BPF for Linux >= 5.8) is required to use eBPF support,
# and CAP_NET_RAW to be able to set the source interface to contact a backend
# If an AppArmor policy is in use, it might have to be updated to allow dnsdist to keep the
# capability: adding a 'capability bpf,' (for CAP_BPF) line to the policy is usually enough.
CapabilityBoundingSet=CAP_NET_BIND_SERVICE
AmbientCapabilities=CAP_NET_BIND_SERVICE
LockPersonality=true
NoNewPrivileges=true
PrivateDevices=true
PrivateTmp=true
# Setting PrivateUsers=true prevents us from opening our sockets
ProtectClock=true
ProtectControlGroups=true
ProtectHome=true
ProtectHostname=true
ProtectKernelLogs=true
ProtectKernelModules=true
ProtectKernelTunables=true
ProtectSystem=full
RestrictAddressFamilies=AF_UNIX AF_INET AF_INET6
RestrictNamespaces=true
RestrictRealtime=true
RestrictSUIDSGID=true
SystemCallArchitectures=native
SystemCallFilter=~ @clock @debug @module @mount @raw-io @reboot @swap @cpu-emulation @obsolete
ProtectProc=invisible
PrivateIPC=true
RemoveIPC=true
DevicePolicy=closed
# Not enabled by default because it does not play well with LuaJIT
# MemoryDenyWriteExecute=true

[Install]
WantedBy=multi-user.target
