MDATA-GET(1m) Metadata Commands MDATA-GET(1m)

mdata-get -- Fetch the value of a metadata key-value pair.

/usr/sbin/mdata-get keyname

The mdata-get command allows the user (or a script) to query the metadata for a guest instance running in a SmartDataCenter (SDC) cloud. Metadata values are generally set programmatically via CloudAPI, or during interactive provisioning via a Web Portal. They may also be set from within the instance with the mdata-put command.

The value of the requested keyname will be printed to stdout. If the metadata service is unavailable at the time of the request, this command will block waiting for it to become available. Non-transient failures, such as the non-existence of the requested keyname, will cause the program to exit with a non-zero status. Depending on the nature of the error, some diagnostic output may be printed to stderr.

The following exit values are returned:


Successful completion.

The requested keyname was available, and its value was emitted to stdout.


Metadata value not found.

The requested keyname was not found in the metadata.


An error occurred.

An unexpected error condition occurred, which is believed to be a non-transient condition. Retrying the request is not expected to resolve the error condition; either a software bug or misconfiguration exists.


A usage error occurred.

Malformed arguments were passed to the program. Check the usage instructions to ensure valid arguments are supplied.

mdata-delete(1m), mdata-list(1m), mdata-put(1m)

October 2013 Joyent SmartDataCenter