gentoo-overlay/app-admin/vault/files/vault.service

[Unit]
Description=vault server
Requires=network-online.target
After=network-online.target

[Service]
User=vault
Environment=VAULT_SERVER_OPTS="-config=/etc/vault.d"
ExecStart=/usr/bin/vault server $VAULT_SERVER_OPTS
CapabilityBoundingSet=CAP_IPC_LOCK
AmbientCapabilities=CAP_IPC_LOCK
Capabilities=CAP_IPC_LOCK=ep
SecureBits=keep-caps
Restart=on-failure
SuccessExitStatus=2

[Install]
WantedBy=default.target