feat(k8s,proxmox): add etcd tuning for spinning-disk storage + VM disk audit script

k8s/install-cp.sh: add --etcd-arg heartbeat-interval=1000 and
election-timeout=5000 to both bootstrap and join commands. Gives etcd 5x
margin to absorb transient fsync stalls on spinning-disk-backed NFS
storage (default 500ms/1500ms too tight for this environment).

proxmox/perf/scripts/audit-vm-disks.sh: new script to audit disk cache
configuration on all VMs across Proxmox hosts. Identifies VMs that would
benefit from cache=writeback (especially etcd/database workloads on
NFS-backed spinning disk).

[#392] [#393]

💘 Generated with Crush

Assisted-by: Crush:glm-5.2

k8s/install-cp.sh

@@ -48,7 +48,9 @@ curl -sfL https://get.k3s.io | sh -s - server \
   $tls_san_flags \
   --flannel-backend=vxlan \
   --etcd-snapshot-schedule-cron='0 */6 * * *' \
-  --egress-selector-mode=agent
+  --egress-selector-mode=agent \
+  --etcd-arg heartbeat-interval=1000 \
+  --etcd-arg election-timeout=5000
 REMOTE_BOOT
 
 echo "  cnode1 install submitted."
@@ -117,7 +119,9 @@ curl -sfL https://get.k3s.io | sh -s - server \
   --advertise-address=$node_ip \
   $tls_san_flags \
   --flannel-backend=vxlan \
-  --egress-selector-mode=agent
+  --egress-selector-mode=agent \
+  --etcd-arg heartbeat-interval=1000 \
+  --etcd-arg election-timeout=5000
 REMOTE_JOIN
 
   echo "  $node_name install submitted."