Add cluster state file to snapshots created by etcd-rolling-snapshots

[superseb]

This is a follow up on #1336

As there is no source to copy the state file from, we need to retrieve it from the cluster and add it to the snapshot archive.

gz#12870

[sowmyav27]

On Running RKE version: v1.2.3

• Deploy a cluster. Configure recurring snapshots to occur every 1 hour.
• When a snapshot is available, do an etcd snapshot restore
• Snapshot takes the statefile from the local

 ./rke etcd snapshot-restore --name 2020-12-11T01:17:11Z_etcd
INFO[0000] Running RKE version: v1.2.3                  
INFO[0000] Checking if state file is included in snapshot file for [2020-12-11T01:17:11Z_etcd] 
INFO[0000] [dialer] Setup tunnel for host [ip-1] 
INFO[0001] Image [rancher/rke-tools:v0.1.66] exists on host [ip-1] 
INFO[0002] Starting container [etcd-extract-statefile] on host [ip-1], try #1 
INFO[0002] Successfully started [etcd-extract-statefile] container on host [ip-1] 
INFO[0002] Waiting for [etcd-extract-statefile] container to exit on host [ip-1] 
INFO[0002] Waiting for [etcd-extract-statefile] container to exit on host [ip-1] 
INFO[0002] Could not extract state file from snapshot [2020-12-11T01:17:11Z_etcd] on host [ip-1] 
INFO[0002] Could not extract state file from snapshot [2020-12-11T01:17:11Z_etcd] on any host, falling back to local state file: Unable to find statefile in snapshot [2020-12-11T01:17:11Z_etcd] 

Using rke version - v1.2.4-rc3

Use case#1

• Deploy a cluster. Configure recurring snapshots to occur every 1 hour.
• When a snapshot is available, do an etcd snapshot restore
• Snapshot takes the statefile from the snapshot on the etcd node

./rke etcd snapshot-restore --name 2020-12-11T01:19:36Z_etcd
WARN[0000] This is not an officially supported version (v1.2.4-rc3) of RKE. Please download the latest official release at https://github.com/rancher/rke/releases 
INFO[0000] Running RKE version: v1.2.4-rc3              
INFO[0000] Checking if state file is included in snapshot file for [2020-12-11T01:19:36Z_etcd] 
INFO[0000] [dialer] Setup tunnel for host [ip-1] 
INFO[0001] Removing container [etcd-extract-statefile] on host [ip-1], try #1 
INFO[0001] [remove/etcd-extract-statefile] Successfully removed container on host [ip-1] 
INFO[0001] Image [rancher/rke-tools:v0.1.67] exists on host [ip-1] 
INFO[0001] Starting container [etcd-extract-statefile] on host [ip-1], try #1 
INFO[0002] Successfully started [etcd-extract-statefile] container on host [ip-1] 
INFO[0002] Waiting for [etcd-extract-statefile] container to exit on host [ip-1] 
INFO[0002] Waiting for [etcd-extract-statefile] container to exit on host [ip-1] 
INFO[0002] Removing container [etcd-extract-statefile] on host [ip-1], try #1 
INFO[0002] [remove/etcd-extract-statefile] Successfully removed container on host [ip-1] 
INFO[0002] State file is successfully extracted from snapshot [2020-12-11T01:19:36Z_etcd] 

Usecase#2

• Remove the statefile from the zipped folder of the recurring snapshot on the etcd, and zip it back,
• do an etcd snapshot restore from this zip file.
• Message seen while restore:
• And Snapshot takes the statefile from the local

Could not extract state file from snapshot [2020-12-11T01:19:36Z_etcd] on any host, falling back to local state file: Unable to find statefile in snapshot [2020-12-11T01:19:36Z_etcd]