20. Release Notes

20.1. Robin Cloud Native Storage v6.0.0-211

The Robin CNS v6.0.0-211 release notes document provides information about upgrade paths, improvements, fixed issues, and known issues.

Release Date: February 23, 2026

20.1.1. Upgrade Paths

The following are the supported upgrade paths for Robin CNS v6.0.0-211:

  • Robin CNS v5.4.18-257 to Robin CNS v6.0.0-211

  • Robin CNS v5.4.18-278 to Robin CNS v6.0.0-211

  • Robin CNS v5.4.18-281 to Robin CNS v6.0.0-211

Note

  • After upgrading to Robin CNS v6.0.0-211, if you are using the Robin Client outside the robincli Pod, you must upgrade to the latest version of the Robin Client.

  • If you have installed Robin CNS with the skip_postgres_operator parameter to use the Zalando PostgreSQL operator, then you must first upgrade the Zalando PostgreSQL operator to v1.11.0 or later before upgrading to Robin CNS v6.0.0-211.

20.1.2. New Features

20.1.2.1. Data Locality Tracking for Volumes

Starting with Robin CNS v6.0.0, Robin CNS provides visibility into the data locality ratio for each volume mount. The data locality ratio indicates the percentage of a volume’s data that is physically stored on the same node where the volume is currently mounted.

If the data locality percentage for a volume is high, I/O operations will be served locally without network hops. This lowers latency and improves storage performance.

The data locality ratio is reported as a percentage between 0% and 100%.

  • Hundred percent (100%) - All leader data for a volume resides on the mount node (fully local).

  • Zero percent (0%) - None of the leader data for a volume resides on the mount node (fully remote).

Viewing data locality ratio

You can view the data locality ratio for a volume using the following ways:

  • The Mount column in the robin volume list command.

  • The Data Locality column in the Mounts table in the robin volume info command.

  • The mount_data_locality label in the robin_vol_mount_node_ids metric.

20.1.2.2. New Metrics

Robin CNS v6.0.0 provides the following new metrics for the CSI sidecar containers and Manager services categories:

20.1.2.2.1. CSI sidecar containers

  • _total (Counters) - Total number of CSI operations (e.g., CreateVolume, DeleteVolume).

  • _errors_total (Counters) - Total number of errors encountered during CSI operations.

  • _duration_seconds (Histograms) - Duration and latency of CSI calls in seconds.

Example

csi_sidecar_operations_seconds_count{driver_name="robin",grpc_status_code="OK",method_name="/csi.v1.Controller/ControllerGetCapabilities"} 1
csi_sidecar_operations_seconds_sum{driver_name="robin",grpc_status_code="OK",method_name="/csi.v1.Controller/ControllerGetCapabilities"} 0.000508898
csi_sidecar_operations_seconds_bucket{driver_name="robin",grpc_status_code="OK",method_name="/csi.v1.Identity/Probe",le="0.1"} 1
20.1.2.2.2. Manager services

  • robin_manager_services_auth_server

  • robin_manager_services_node_monitor_server

  • robin_manager_services_control_infra_server

For more information, see Storage Metrics.

20.1.3. Improvements

20.1.3.1. Enhanced Master Pods upgrade strategy

Starting with Robin CNS v6.0.0, the Robin master Pods upgrade sequentially to ensure continuous service and prevent downtime.

With this enhancement, Robin CNS first upgrades the standby master Pods. Once the standby master Pods are upgraded successfully, it upgrades the active master Pod.

20.1.4. Fixed Issues

Reference ID

Description

RSD-10850

The issue that caused unnecessary slice leader changes during iomgr-server restarts is fixed.

RSD-10242

The Robin worker Pod is crashing due to the empty /etc/robin/rcm/config.ini file. This issue is fixed.

RSD-10160

The issue where VolumeAttachment jobs could get stuck due to a race condition and lock contention within the job manager and prevent volume mount and unmount operations from progressing is fixed.

RSD-10372

The lease mechanism feature in Robin CNS failed to handle the temporary etcd connection interruptions, resulting in frequent Robin master failovers. This issue is fixed.

RSD-11041

The issue of Robin cluster resource reporting the NotReady status for an extended period of time is fixed. The backoff time is adjusted to display accurate cluster status.

RSD-10603

During the Robin CNS upgrade, IOMgr failed to start because of the empty /etc/consul/client/checks.json file on the node. This issue is fixed.

RSD-11044

The DaemonSet robin-tcmuproxy priorityClass was not set to critical. This issue is fixed. In this version, it is set to critical.

RSD-11042

The issue of the standby Robin master pod failing its readiness probe and becoming unhealthy due to a mismatch between the in-memory phase state and the value stored in /etc/robin/robin_master/phase is fixed.

20.1.5. Known Issue

Reference ID

Description

PP-41215

Symptom

Under rare scenarios, a VM volume’s slice leader can temporarily appear on two nodes. This happens if the I/O Manager (IOMgr) is down for an extended period, active I/O occurred on volumes, and the IOMgr is then restarted. The issue is due to a race condition between Robin Cluster Manager (RCM) updating node/device states and the IOMgr initiating remounts. However, this issue corrects itself once the volume slice leader automatically consolidates to the mounted node once volume slices resynchronize.

PP-40480

Symptom

In rare scenarios, you might observe that one of the Pods is stuck in the ContainerCreating state, and the kubectl describe pod command shows the following volume mount error:

Failed to mount volume pvc-d16fa6b1-5bcb-4c69-805d-ab4df9018cee: Node <default:vnode-87-237> has mount_blocked STORMGR_NODE_BLOCK_MOUNT. No new mounts are allowed.

Workaround

Bounce the worker Pod running on the affected node.

PP-39632

Symptom

After upgrading to Robin CNP v6.0.0, NFS client might hang with no pending IO message.

For no pending IO, refer this path : /var/log/robin/nodeplugin/robin-csi.log with the following message:

CsiServer_9 - robin.utils - INFO - Executing command
/usr/bin/nc -z -w 6 2049 with timeout 60 seconds
CsiServer_9 - robin.utils - INFO - Command
/usr/bin/nc -z -w 6 2049 completed with return code 0.
CsiServer_9 - robin.utils - INFO - Standard out:

Also, you can find the following message in the dmesg:

nfs: server 192.02.1.218 not responding, timed out
nfs: server 192.02.1.218 not responding, timed out
nfs: server 192.02.1.218 not responding, timed out

Workaround

  1. Check the node provisioner logs where the PVC is checking for the path and it is hung.

  2. For the deployment/statefulset that is using the problematic PVC, scale down the replica count to 0.

  3. Ensure all Pods associated with the application have terminated.

  4. Scale up the replica count back to the original value.

PP-34414

Symptom

In rare scenarios, the IOMGR service might fail to open devices in the exclusive mode when it starts as other processes are using these disks. You might observe the following issues:

  • All app Pods restart, and some app Pods get stuck in the ContainerCreating state.

To confirm the above issues, complete the following steps:

  1. Check for the EVENT_DISK_FAULTED event type in the disk events:

    # robin event list --type EVENT_DISK_FAULTED

  2. If you see the disk is faulted error, check the IOMGR logs for dev_open() error and Failed to exclusively open message on the node where disks are present.

    # cat iomgr.log.0 | grep <device> | grep "dev_open"

  3. If you see the Device or resource busy error in the log file, use fuser command with the device path to confirm whether the device is in use:

    # fuser /dev/disk/by-id/scsi-SATA_Micron_M500_MTFD_1401096049D5

Workaround

If the device is not in use, restart the IOMGR service on the respective node:

# supervisorctl restart iomgr-server

20.1.6. Technical Support

Contact Robin Technical support for any assistance.