ZStack Cloud 4.4.0>Tutorials>Private Cloud>Upgrade Tutorial>Considerations

Considerations

When you upgrade ZStack Cloud, note that:

During the upgrading, the management nodes are inaccessible and you cannot apply VM and volume resources. Therefore, we recommend that you upgrade the cloud platform during business troughs to avoid resource application and business change needs.
After the management node upgrading is completed, all hosts, primary storages, backup storages, VPC vRouters are reconnected and related resources are auto-upgraded. During the connection, you cannot perform operations on VM instances and volumes.
If an error occurs during the upgrading and interrupts the upgrading, you can troubleshoot the error. After the error is solved, you can upgrade the cloud platform again.

Starting from ZStack Cloud 4.3.12, the QEMU version is automatically upgraded from 2.12 to 4.2.
- If you deploy a new Cloud by using the ISO of 4.3.12 or a later version, QEMU 4.2 is installed by default. If you upgrade your Cloud to 4.3.12 or a later version, QEMU 2.12 is used by default.
- To use the Cloud properly, make ensure that all hosts in the same cluster use the same QEMU version. Therefore, if you upgrade your Cloud to 4.3.12 or a later version, you could not expand the capacity by adding hosts (installed using the ISO of 4.3.12 or a later version) to the existing cluster. To expand the capacity, use a new cluster.
Starting from ZStack Cloud 4.0.0, we bring you the following enhancements:
- vRouter is upgraded to VPC vRouter.
  Starting from 4.0.0, vRouter is upgraded to VPC vRouter and vRouter network is upgraded to VPC network. vRouter is no longer available on the UI. The seamless upgrade does not affect your business continuity.
- User Group and User are replaced by Enterprise Management Account System.
  Starting from 4.0.0, User Group and User are replaced by Enterprise Management Account System. User Group and User are no longer available on the UI. You cannot login to the Cloud by using a user or user group account. Before you implement upgrading, migrate the user and user group account data to Enterprise Management.
  Note: User accounts created by the admin and have the admin permissions are also cancelled. Platform admins in Enterprise Management have the equivalent permissions. You can use Enterprise Management to create platform managers based on your business needs.
- The integration of AD/LDAP and accounts is adjusted.
  Starting from 4.0.0, the integration of AD/LDAP and accounts is managed by Enterprise Management. Before you implement upgrading, migrate the AD/LDAP account data managed by the original account system to Enterprise Management.
Starting from ZStack Cloud 3.9.0, if you use c74 ISO and QEMU 2.9, the libvirt version is automatically upgraded to 4.9.0.
- If you use open-source Ceph distributed storage and enable the CEPHX (Ceph authentication) feature, when you hot-plug VM CD-ROM, an error may occur because libvirt of the new version does not support hot plugging. You can contact the official technical support when necessary.
- Starting from 3.2.0, libvirt updates the format of shared volumes to raw. Therefore, when you create a shared volume, the format of the volume is raw. This type of volume does not allow you to create snapshots and resize capacities, or create images for powered-on VM instances to which this type of volume is attached. In later versions of ZStack Cloud, these limitations will be eliminated.
- The libvirt auto-upgrading feature is enabled by default. You can disable the feature by using the following method:
  Enter /usr/local/zstack/apache-tomcat/webapps/zstack/WEB-INF/classes/ and set the following parameter in the zstack.properties configuration file:
```
updatePkgWhenConnect = false
# Disable libvirt auto-upgrading.
```
  Restart the management node to make the modification take effect.
Starting from ZStack Cloud 3.7.1, ISO of the c76 and c74 editions are available and multiple repos are supported. When you upgrade the cloud platform, note that:
- Starting from 3.7.1, ISO of the c72 edition is no longer used for installation and deployment of the new cloud platform. If you need to expand the capacity or upgrade the operating system, contact the official technical support for help.
- Starting from 3.7.1, the local repo of ISO of the c72 edition is redirected to ISO of the c74 edition. If you use offline upgrading, you need to obtain ISO of the c74 edition to update the local repo.

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