Metro node: Password-less SSH to a node or director fails

Summary: This article talks to the issue when attempting to access any metro node node/director, you are prompted for a password. This is not an expected behavior as metro node supports password-less SSH between the nodes/director(s) when using the service account. ...

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Symptoms

Impacted metro node Hardware:
Dell Hardware: Metro Node-mn114/mn215
Dell Hardware: Metro node - Local or Metro

Note: The metro node mn215 only supports metro node OS 8.0.0 and later.

 

Impacted metro node OS versions:
Dell Software: Metro node OS 7.x
Dell Software: Metro node OS 8.x

 

Issues:
When attempting to SSH to any Metro Node node or director(s) with the service account, you are prompted to input a password as follows:

Example: (The below output depicts that node-B is unable to perform password-less SSH to Node-A)

service@director-1-1-b:~> ssh 128.221.252.35
Password:

 

Symptoms:
All directors reporting director-x-y-z : Systemd IO error: Cannot determine the state of system on the 'cluster status' output as follows:

Example:

VPlexcli:/> cluster status
WARNING: There are unreachable directors: director-1-1-A. Connectivity may still have errors even if none are reported.

Cluster cluster-1
        operational-status:            degraded
        transitioning-indications:     disk(s) not visible from all directors,meta data problem
        transitioning-progress:
        health-state:                  degraded
        health-indications:            director-1-1-A : Systemd IO error:  Cannot determine the state of system services

        local-com:                     connectivity: NONE

LC-00 ports - FAIL - Failed to determine expected connectivity.
LC-01 ports - FAIL - Failed to determine expected connectivity.

Cluster Name Port Group MTU  Connectivity Status
------------ ---------- ---- ------------ -----------
cluster-1    LC-00      1500 fail         all-enabled
             LC-01      1500 fail         all-enabled
cluster-2    LC-00      1500 fail         all-enabled
             LC-01      1500 fail         all-enabled

     man-com:                       connectivity: NONE

MC-01 ports - FAIL - Failed to determine expected connectivity.
MC-00 ports - FAIL - Failed to determine expected connectivity.

Cluster Name Port Group MTU  Connectivity Status
------------ ---------- ---- ------------ -----------
cluster-1    MC-00      1500 fail         all-enabled
             MC-01      1500 fail         all-enabled
cluster-2    MC-00      1500 fail         all-enabled
             MC-01      1500 fail         all-enabled

Cluster cluster-2
        operational-status:            ok
        transitioning-indications:
        transitioning-progress:
        health-state:                  ok
        health-indications:
        local-com:                     ok
        man-com:                       ok

wan-com: ok

 

Cause

This issue may occur if service directory permissions are modified to full access (777) (Read, write, and run permissions)

 

Resolution

Workaround Steps:

  1. Log in to the affected node with service user and go to service-maintenance-window by entering the below command from the service/Linux prompt:

    sudo /usr/sbin/service-maintenance-window -f

  2. Check and change the permissions defined for the service directory on the affected node as follows:

    Example: (Affected metro node node-A as per symptom section)

    From:
director-1-1-a:/home # ll
total 28
drwxr-x---  6 admin      users  4096 Aug 20  2021 admin
drwxr-x---  6 eseservice users  4096 Aug 20  2021 eseservice
drwx------  2 root       root  16384 Mar  3  2022 lost+found
drwxrwxrwx 11 service    users  4096 May 20 05:08 service

To:
director-1-1-a:/home # chmod 750 service
director-1-1-a:/home # ll
total 28
drwxr-x---  6 admin      users  4096 Aug 20  2021 admin
drwxr-x---  6 eseservice users  4096 Aug 20  2021 eseservice
drwx------  2 root       root  16384 Mar  3  2022 lost+found
drwxr-x--- 11 service    users  4096 May 20 05:08 service

  3. Attempt to SSH back to the affected node as the service user and confirm if you can SSH password-less or not as follows:

    Example: (The below output shows that Node-B can perform password-less SSH to node-A successfully)

    service@director-1-1-b:~> ssh 128.221.252.35
Last login: Mon May 20 05:32:04 2024 from 10.107.104.132
service@director-1-1-a:~>

  4. Run the cluster status command again to confirm no errors were seen:

    VPlexcli:/> cluster status
Cluster cluster-1
        operational-status:            ok
        transitioning-indications:
        transitioning-progress:
        health-state:                  ok
        health-indications:
        local-com:                     ok
        man-com:                       ok


Cluster cluster-2
        operational-status:            ok
        transitioning-indications:
        transitioning-progress:
        health-state:                  ok
        health-indications:
        local-com:                     ok
        man-com:                       ok


wan-com: ok

 

Additional Information

*Using chmod in absolute mode*
In the absolute mode, permissions are represented in numeric form (octal system to be precise). In this system, each file permission is represented by a number.

 

r (read) = 4
w (write) = 2
x (execute) = 1
– (no permission) = 0
With these numeric values, you can combine them and thus one number can be used to represent the entire permission set.

 

Number Permission
0 —
1 –x
2 -w-
3 (i.e. 2+1) -wx
4 r–
5 (i.e. 4+1) r-x
6 (i.e. 4+2) rw-
7 (i.e. 4+2+1) rwx

 

Affected Products

metro node, metro node mn-114, metro node mn-215
Article Properties
Article Number: 000225209
Article Type: Solution
Last Modified: 21 May 2024
Version:  1
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