Raise severity from warning to critical

Partial-Bug: PROD-15203
Change-Id: I32f19b5520bc200d61280da57f4ab5842b060454

Change-Id: I67531b6ad15a2e96ee05178f17aae2504b3362bf

The other disk alerts use predict_linear() to trigger before a disk gets
full but they don't trigger when the disk is effectively (or nearly)
full.

Change-Id: I8e6794d35bf96378ca3e3d527db4315d2b3a868d

Change-Id: I1c8e752de9ad3479da830706ae736df6846b977f

Change-Id: Ia7df4918732ce8fcf28b1d6eed629073146a567c

Since metrics on dropped packets are counters, the alerts should use
the rate() function. This change also fixes some inconsistencies in the
alert descriptions.

Change-Id: I9abbc0a49f45ba760836c436a3e7e65aa62f652e

Change-Id: I1cc00b41a6a1774d1401a9f71ab4c6364c65d139

Change-Id: Idc73c152a0e71d5ac2a8c10f46c955755d8e77ae

This change adds the Telegraf configuration to collect swap metrics, the
associated Prometheus alarms and graphs to the Grafana dashboard.

Change-Id: I3595fd0b8cab06215c620642da69dd29c398396a

Change-Id: If50f18367b22338b3fba1ff15902d557a0bdf2ea

Change-Id: I54e02e0741d53ec7b2335145dc968b7b8c8f5e00

Change-Id: I1765fc6aa4a8c3da25330f19bb043ddbf548b9ad

Change-Id: I66576b4ed40ef160c5f13747a908f018f252b6b4