Basic Maintenance

This chapter mainly describes how to troubleshoot ZStack abnormal basic operations.

Installation and Deployment

If you fail to install, deploy, and upgrade ZStack, troubleshoot the following:

When installing an operating system, you select ZStack Enterprise Management Node. However, after installation, you have not installed ZStack.
Cause
- The minimum hardware requirement is not met (4-core CPU or 8-G memory).
- When installing the operating system, you have not configured a proper IP address. This is because the ZStack management node must have available IP addresses.
Solution
- At this time, run bash /opt/zstack*installer.bin -E to install ZStack Enterprise.
- Or, run bash /opt/zstack*installer.bin to install ZStack Community.
When you install ZStack, the following error is reported:
Symptom
```
Fail Reason: /usr/local/zstack is existing. Please delete it manually before installing a new ZStack
```
Cause
At this time, the system has ZStack installed without allowing you to reinstall the Cloud.
Solution
- If you want to upgrade the Cloud, use -u directly.
- If you want to reinstall the Cloud, run rm -rf /usr/local/zstack; bash zstack-installer.bin -D.
After you fail to install and deploy the Cloud, the failure information will be displayed on the screen.
Solution
Check /tmp/zstack_installation.log. Based on the error tips, try to address this problem by yourself.
During upgrade, ZStack ISO versions are incompatible and, then, the following error will be reported:
Cause:
```
mount: /dev/loop0 is write-protected, mounting read-only /root Current release c76 not matched the new ISO c74, Use zstack-upgrade -r xxx.iso to update current repo, Use zstack-upgrade -a/--add_repo xxx.iso to add a new repo
```
Solution
To solve this problem
1. Download the latest ISO image on your management node. For example, run the following command on the management node:
```
wget http://cdn.zstack.io/product_downloads/iso/ZStack-x86_64-DVD-3.10.0-c76.iso
```
2. Run the following command to upgrade the Cloud. Yum repositories that are upgraded in the ISO image will be synchronized locally, and then the management node can be upgraded directly.
```
zstack-upgrade ZStack-x86_64-DVD-3.10.0-c76.iso
```
When you upgrade ZStack, custom developments or database modifications will cause upgrade failure. Hence, you want to restore the original ZStack.
Prerequisites
When you upgrade ZStack, the currently core files and the database default to be backed up to a corresponding directory.
1. ZStack core files will be backed up to the /usr/local/zstack/upgrade/ directory, and their file name will be named after the time when the Cloud is upgraded. Assume that the file name is 2017-11-09-15-41-52.
2. The database defaults to be backed up to the /usr/local/zstack/db_backup/ directory, and their file name will be named after the time when the Cloud is upgraded. Assume that the file name is 2017-11-09-15-42-43, while the backup file is backup.sql.
Procedure
1. Back up the former version of the ZStack core files, and run the following command:
```
cp /usr/local/zstack/upgrade/2017-11-09-15-41-52 /root -r
```
2. Back up the former version of the database, and run the following command:
```
cp /usr/local/zstack/db_backup/2017-11-09-15-42-43/backup.sql /root
```
3. Back up the current database again, and run the following command:
```
zstack-ctl dump_mysql
```
4. Delete the current ZStack environment, and run the following command:
```
zstack-ctl stop rm -rf /usr/local/zstack
```
5. Use the former installation package to install ZStack directly:
```
bash ZStack-enterprise-installer.bin -D
```
6. Restore the ZStack core files backed up in the step 1:
```
zstack-ctl stop mv /usr/local/zstack/apache-tomcat/webapps/zstack /usr/local/zstack/apache-tomcat/webapps/zstack-bk cp /root/2017-11-09-15-41-52/zstack /usr/local/zstack/apache-tomcat/webapps  -r chown zstack:zstack /usr/local/zstack/apache-tomcat/webapps/zstack -R
```
7. Restore the database backed up in the step 2:
```
cat /root/backup.sql |mysql -u root -pzstack.mysql.password zstack
```
8. Start the ZStack management node. At this time, ZStack has restored successfully to the version before the original version failed.
```
zstack-ctl start
```
If you install ZStack via the All-in-One method, we recommend that you set ReservedMemory. The following are three types of granular methods to set the reserved memory for a host:
- Global Settings
  Navigate to Settings > Global Settings > Basic Settings, and set ReservedMemory. Default value: 1G.
  Note: If your cluster or host has been configured with this option, this global setting will not take effect for this cluster or host.
- Cluster
  Navigate to Hardware > Cluster, and select a cluster to go to the cluster details page. On the Global Settings tab page, set ReservedMemory. Default value: 1G.
  Note: If your host has been configured with this option independently, the global setting for this cluster will not take effect for this host.
- Host
  Currently, you can set the reserved memory for a single host via CLI. For example,
```
UpdateResourceConfig category=kvm name=reservedMemory resourceUuid=e2f4836723a2490095768fe611c540b1 value=10G # resourceUuid is the UUID of the host, while the value is the reserved memory of the host.
```

Start Service

After the related ZStack services are rebooted on your management node, these services will be started automatically.

If you fail to start the ZStack service, troubleshoot the following:

The database works properly.
Run systemctl status/start/stop/restart mariadb to check the status of, or start, stop, and reboot the database.
The following error is reported:
Symptom
```
ERROR: failed to connect to the mysql server[hostname:10.0.0.18, port:3306, user:zstack, password:zstack.password]
```
Solution
- Ensure that the IP addresses, user name, and password related to the database under the /usr/local/zstack/apache-tomcat/webapps/zstack/WEB-INF/classes/zstack.properties file path are all correct, and the database can be accessed via the mysql command.
- For example, run mysql -u zstack -pzstack.password -h 10.0.0.18 to access the database directly.
The following error is reported:
Symptom
```
8080 is occupied by some process. Please use netstat to find out and stop it
```
Solution
Run netstat -anp|grep 8080 to find the program that is occupied by port 8080 and then to stop port 8080 before starting ZStack.
The following error is reported:
Symptom
```
MN status: Unknown, the management node seems to become zombie as it stops responding APIs
```
Cause and Solution
Generally, memories are out of capacity, so the message bus is not correctly handled. Expand the memories. At this time, we recommend that you not use the management node to act as a compute node and add this compute node to ZStack.

zstack-ctl Commands

ZStack lets you manipulate services or resources via zstack-ctl.

The following are common zstack-ctl commands:

Check status: zstack-ctl status
Manipulate service: zstack-ctl stop/start/stop_ui/start_ui/start_node/stop_node/restart_node/
Collect log: zstack-ctl configured_collect_log
Back up database: zstack-ctl dump_mysql
Restore database: zstack-ctl restore_mysql -f back.gz --mysql-root-password password
Change IP address for management node: zstack-ctl change_ip
Check configuration: zstack-ctl show_configuration
Check UI configuration: zstack-ctl show_ui_configuration
Install license: zstack-ctl install_license -f license_key.txt
Reset admin password: zstack-ctl reset_password
Change database password: zstack-ctl change_mysql_password --root-password zstack.mysql.password --user-name zstack --new-password password

Note:

For more information about zstack-ctl commands, see zstack-ctl Command Manual in ZStack Documentation.

Basic Maintenance

Installation and Deployment

Start Service

zstack-ctl Commands

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