Upgrading ESXi hosts from SDDC manager fails on prechecks with the error "ESXi CLI checks for legacy boot mode and host filesystem have failed"

Products

• VMware SDDC Manager

Issue/Introduction

Symptoms:

• While running prechecks the SDDC manager reports an error when attempting to perform the legacy boot mode and filesystem symlinks CLI checks on the hosts:
  
  
  
  
• Hosts do not use legacy boot mode and no broken symlinks are to be found in the ESXi filesystem
• Operations manager logs shows errors similar to the excerpt below:
  
  operationsmanager.log
  ERROR [vcf_om,6719f51a97b5805d99b9df8d2ce46477,0ea7] [c.v.e.s.c.u.c.SshCommandExecuter,precheck-validation10] Could not connect to the SSH server @ esxi.domain.com for configuration.
com.jcraft.jsch.JSchException: timeout: socket is not established
        at com.jcraft.jsch.Util.createSocket(Util.java:394)
        at com.jcraft.jsch.Session.connect(Session.java:215)
        at com.vmware.evo.sddc.common.util.SshUtil.getSession(SshUtil.java:678)
        at com.vmware.evo.sddc.common.util.SshUtil.getSession(SshUtil.java:626)
        at com.vmware.evo.sddc.common.util.command.SshCommandExecuter.<init>(SshCommandExecuter.java:55)
        at com.vmware.evo.sddc.common.util.command.SshCommandExecuterFactory.createSshCommandExecuter(SshCommandExecuterFactory.java:71)
        at com.vmware.evo.sddc.common.util.command.SshCommandExecuterFactory.createSshCommandExecuter(SshCommandExecuterFactory.java:28)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:569)

Environment

VMware Cloud foundation 5.x

Cause

The prechecks are failing due to a communication problem of the SDDC manager with the ESXi hosts on port 22

Resolution

Investigate network and TCP/UDP port connectivity issues on port 22 using KB article 341078

Additional Information

Network port requirements for VMware Cloud Foundation