Port zfs_zpool.sh to Python

[lstrojny]

• Ports the shell script to Python
• Introduces new metrics from zfs_status

New metrics

zfs_zpool_status The status of the zpool
zfs_zpool_vdev_info Information about the vdevs in a zpool
zfs_zpool_scrub_duration_seconds The duration of the latest zpool scrub in seconds
zfs_zpool_scrub_corrected_bytes The number of corrected bytes of the latest zpool scrub
zfs_zpool_scrub_time_seconds The timestamp of the latest zpool scrub
zfs_zpool_resilvering_duration_seconds The duration of the latest zpool scrub in seconds
zfs_zpool_resilvering_corrected_bytes The number of corrected bytes of the latest zpool scrub
zfs_zpool_resilvering_time_seconds The timestamp of the latest zpool scrub

[SuperQ]

Are the ZFS scripts necessary anymore? The node_exporter has a full ZFS collector module now.

[lstrojny]

Yup, the metrics provided here are not exposed by node exporter.