Issue/Introduction

This article describes how to troubleshoot inability to connect to a VM instance over SSH. It applies to the initial diagnosis and resolution of similar issues in ZStack Cloud.

Environment

• Product: ZCF
• Component: Cloud
• Version: 3.x-5.5.30

Resolution

Check network connectivity and ensure that the network and port can communicate normally, and then try the following methods:

• If the Linux security policy marks the account as expired, sign-in fails. Run chage -l root to view the account expiration date. You can run chage -E -1 root to configure the account to never expire.
• If the SSH client, such as SecureCRT, and the SSH server do not support any common SHA algorithms, SSH access might fail. Adjust the SSH client or server configuration so that both sides support at least one common SHA algorithm.
• Set UseDNS to no.
• Check whether the default cloud-init configuration disables password-based sign-in.