dmg

DAOS Management Tool (dmg)

The DAOS Management Tool is a system administration application for DAOS. Unlike other DAOS client applications that require authentication through DAOS agent, dmg is capable of authenticating directly through local certificates.

The management tool has limited software dependencies as tasks are performed on remote servers over RPC and as such is suitable to be run from a login node.

Commandline interface

The go-flags package is used to implement a commandline interface. Command tree is built starting with top-level commands defined in the cliOptions struct defined in main.go, subcommands are then defined in functionality specific files as described below. Desired behavior on (sub-)command execution is then defined in the subcommand type's Execute method.

Certificates

Local certificate locations can be specified in the client config file.

For more details on how certificates are used within DAOS, see the Security documentation.

Communications

The management tool is a gRPC client and uses the control API to interact with multiple daos_server processes in parallel. The control API invokes RPCs to daos_server instances, each of which run a listening gRPC server that hosts the control service.

Communications take place over the management network and addresses of remote storage servers to connect to can be specified as a LLNL-style hostlist (compact representation for a number of similarly-named hosts, e.g. foo[1-1024], bar[35,42,55-64], etc) on the commandline or in the client config file.

For details on how gRPC communications are secured and authenticated, see the Security documentation.

Usage documentation

The dmg man page can be automatically updated when adding or modifying commands by running go test -v -run TestDmg_ManPageIsCurrent -args --update, unit tests will fail if this isn't run. Implementation in man_test.go.

Functionality

The functionality provided by the management tool is split into domains which map to individual subcommands.

For exhaustive subcommand listings please see output of dmg [<subcommand>] --help.

Config

Provides capability to automatically generate recommended server config file for a given set of hosts. Implementation in auto.go.

Container

Provides capability to change the owner of a DAOS container. Implementation in cont.go.

Firmware

Firmware related capabilities are selectively compiled and may not be present in all builds. Provided capability to query and update firmware on NVMe and PMem devices. Implementation with firmware enabled in firmware.go. When disabled: firmware_disabled.go.

Network

Provides capability to manage and enumerate available network devices. Implementation in network.go.

Pool

Provides capability to create, destroy and manage DAOS storage pools including ability to manage individual properties and pool Access Control Lists. Online Server Addition related commands provide capability drain, evict, exclude, extend and reintegrate. Implementation in pool.go and ACL functionality and helpers in acl.go.

Storage

Provides capability to scan available storage devices, provision relevant hardware and format allocated storage for use with DAOS. Implementation in storage.go.

The capability to run queries on a particular device as well as setting particular device properties is also provided. Sub-commands of dmg storage query ... are implemented in storage_query.go.

System

Provides capability to query system members/ranks that have previously joined the DAOS system. Additionally perform controlled stop and start on members/ranks recorded in the system membership. Implementation in system.go.

Unit tests

Unit tests are provided for each functionality file (filename suffixed with _test.go). Command syntax is verified by tests that call into helper methods within command_test. Command handlers are automatically checked to verify meaningful output is provided when the --json flag is set.