osctl-exportfs 8 2024-06-04 24.05.0

NAME

osctl-exportfs - manage dedicated NFS servers for filesystem exports

SYNOPSIS

osctl-exportfs [global options] command [command options] [arguments...]

DESCRIPTION

osctl-exportfs manages dedicated NFS servers run in lightweight containers for that purpose. Each NFS server runs in its own network namespace, which is useful for accounting and ensuring quality of service. Each NFS server also has a custom set of exported filesystems.

osctl-exportfs utility can only be used in conjuction with the osctl-exportfs service, which has to be enabled in system configuration using option osctl.exportfs.enable, see configuration.nix(5). The created NFS servers are not persistent. The servers and their configuration is lost when the host machine is rebooted.

Each NFS server lives in its own privileged container composed of mount, network, UTS and PID namespace, but sharing the host's /nix/store. Servers can be started either interactively using command server spawn or put into runit supervision tree using command server start. Servers monitored by runit are automatically restarted in case they inadvertedly stop.

COMMANDS

server ls [options]: List configured NFS servers and their state.

-H, --hide-header Do not show header, useful for scripts.

-L, --list List available parameters and exit.

-o, --output parameters Select parameters to output, comma separated.

-s, --sort parameters Sort output by parameters, comma separated.

server new [options] name: Add a new NFS server identified by name.

-a, --address address The server will be listening on address if provided. It is saved into the configuration file for later use with server spawn and server start. address has to be an IPv4 address without prefix.

--netif netif Name of the server's network interface on the host system. Defaults to nfs-<server>.

--nfsd-port port Configure port for rpc.nfsd, useful if server is behind firewall.

--nfsd-nproc nproc Specify the number of NFS server threads. By default, eight threads are started. However, for optimum performance several threads should be used.

--[no-]nfsd-tcp Instruct the kernel nfs server to open and listen on a TCP socket.

--[no-]nfsd-udp Instruct the kernel nfs server to open and listen on a UDP socket.

--nfs-versions versions Allow only selected NFS versions. Possible values are: 3, 4, 4.0, 4.1 and 4.2, separated by commas.

--nfsd-syslog By default, rpc.nfsd logs error messages (and debug messages, if enabled) to stderr. This option makes rpc.nfsd log these messages to syslog instead. Note that errors encountered during option processing will still be logged to stderr regardless of this option.

--mountd-port port Use fixed port for rpc.mountd, useful if server is behind firewall.

--lockd-port port Use a fixed port for the NFS lock manager kernel module (lockd/nlockmgr). This is useful if the NFS server is behind a firewall.

--statd-port port Use a fixed port for rpc.statd. This is useful if the NFS server is behind a firewall.

server del name: Delete configured NFS server identified by name.

server set options name: Configure server options. Changes are saved to the server's configuration file. If the server is running, changes will take effect when it is restarted.

--netif netif Name of the server's network interface on the host system. Defaults to nfs-<server>.

--nfsd-port port Configure port for rpc.nfsd, useful if server is behind firewall.

--nfsd-nproc nproc Specify the number of NFS server threads. By default, eight threads are started. However, for optimum performance several threads should be used.

--[no-]nfsd-tcp Instruct the kernel nfs server to open and listen on a TCP socket.

--[no-]nfsd-udp Instruct the kernel nfs server to open and listen on a UDP socket.

--nfs-versions versions Allow only selected NFS versions. Possible values are: 2, 3, 4, 4.0, 4.1 and 4.2 separated by commas.

--mountd-port port Use fixed port for rpc.mountd, useful if server is behind firewall.

--lockd-port port Use a fixed port for the NFS lock manager kernel module (lockd/nlockmgr). This is useful if the NFS server is behind a firewall.

--statd-port port Use a fixed port for rpc.statd. This is useful if the NFS server is behind a firewall.

server spawn [options] name: Start NFS server name and export its filesystems.

The server will run in the foreground, it can be stopped by sending the process SIGINT or SIGTERM signal.

server start [options] name: Start NFS server name, but put in a runit supervision tree. A runsv service is created in /run/osctl/exportfs/runsvdir, which is picked up and started by runsvdir running as part of osctl-exportfs service.

server stop name: Remove the service for NFS server name from runit supervision tree and stop it.

server restart [options] name: Restart NFS server name, which has to be running in a runit supervision tree.

server attach name: Attach into the NFS server container and run an interactive shell.

export ls [server]: List all exports or exports configured on server.

export add options server: Export directory using NFS server server.

--directory dir Directory from the host namespace to export. Required.

--as dir Change the path the directory will be exported as. Optional.

--host host Which hosts will be allowed to mount the export. Required.

--options options Optional NFS export options.

export del options server: Remove export from NFS server server with matching dir and host.

--as dir Exported directory.

--host host Hosts allowed to mount the exported directory.

FILES

All configured NFS servers reside in /run/osctl/exportfs, which is initialized by the osctl-exportfs service:

/run/osctl/exportfs
├── rootfs/
├── runsvdir/
└── servers/

Directory rootfs/ is used to construct a new root filesystem for the server container and is always empty on the host. Directory runsvdir/ is monitored by the runsvdir program from runit, i.e. services for servers started using server start are put into this directory. Directory servers/ contains a subdirectory per NFS server, each with its own configuration.

Server directory

Each server directory has the following structure:

<server name>
├── runsv/
├── shared/
├── state/
├── config.yml
├── exports
├── lock
└── [pid]

Directory runsv/ is the service generated by command server start. It is linked to /run/osctl/exportfs/runsvdir as long as the server should be running.

Directory shared/ is used to propagate new mounts from the host to the NFS container in order to add new exports.

NFS server state, normally found in /var/lib/nfs is stored in directory state/.

config.yml contains server configuration, including exports. It is used by osctl-exportfs to generate exports, which is then read by exportfs(8) to actually configure the containerized NFS server.

File lock is used for synchronization. If the server is running, the PID of its init is stored in file pid.

BUGS

Report bugs to https://github.com/vpsfreecz/vpsadminos/issues.

ABOUT

osctl-exportfs is a part of vpsAdminOS.