Using live migration
by Tony Campbell, Egle Sigler, Cody Bunch, Kevin Jackson, Sunil Sarat, Alok Shrivas
OpenStack: Building a Cloud Environment
- OpenStack: Building a Cloud Environment
- Table of Contents
- OpenStack: Building a Cloud Environment
- OpenStack: Building a Cloud Environment
- Credits
- Preface
- 1. Module 1
- 1. An Introduction to OpenStack
- 2. Authentication and Authorization Using Keystone
- Identity concepts in Keystone
- Architecture and subsystems
- Installing common components
- Installing Keystone
- Verifying the installation
- Troubleshooting the installation and configuration
- Summary
- 3. Storing and Retrieving Data and Images using Glance, Cinder, and Swift
- Introducing storage services
- Working with Glance
- Working with Cinder
- Working with Swift
- Troubleshooting steps
- Summary
- 4. Building Your Cloud Fabric Controller Using Nova
- 5. Technology-Agnostic Network Abstraction Using Neutron
- The software-defined network paradigm
- Neutron
- Installing Neutron
- Troubleshooting Neutron
- Summary
- 6. Building Your Portal in the Cloud
- 7. Your OpenStack Cloud in Action
- 8. Taking Your Cloud to the Next Level
- Working with Heat
- Ceilometer
- Installing Ceilometer
- Installing Ceilometer on the compute node
- Installing Ceilometer on the storage node
- Testing the installation
- Billing and usage reporting
- Summary
- 9. Looking Ahead
- A. New Releases
- 2. Module 2
- 1. Keystone – OpenStack Identity Service
- Introduction
- Installing the OpenStack Identity Service
- Configuring OpenStack Identity for SSL communication
- Creating tenants in Keystone
- Configuring roles in Keystone
- Adding users to Keystone
- Defining service endpoints
- Creating the service tenant and service users
- Configuring OpenStack Identity for LDAP Integration
- 2. Glance – OpenStack Image Service
- Introduction
- Installing OpenStack Image Service
- Configuring OpenStack Image Service with OpenStack Identity Service
- Configuring OpenStack Image Service with OpenStack Object Storage
- Managing images with OpenStack Image Service
- Registering a remotely stored image
- Sharing images among tenants
- Viewing shared images
- Using image metadata
- Migrating a VMware image
- Creating an OpenStack image
- 3. Neutron – OpenStack Networking
- Introduction
- Installing Neutron and Open vSwitch on a dedicated network node
- Configuring Neutron and Open vSwitch
- Installing and configuring the Neutron API service
- Creating a tenant Neutron network
- Deleting a Neutron network
- Creating an external floating IP Neutron network
- Using Neutron networks for different purposes
- Configuring Distributed Virtual Routers
- Using Distributed Virtual Routers
- 4. Nova – OpenStack Compute
- Introduction
- Installing OpenStack Compute controller services
- Installing OpenStack Compute packages
- Configuring database services
- Configuring OpenStack Compute
- Configuring OpenStack Compute with OpenStack Identity Service
- Stopping and starting nova services
- Installation of command-line tools on Ubuntu
- Using the command-line tools with HTTPS
- Checking OpenStack Compute services
- Using OpenStack Compute
- Managing security groups
- Creating and managing key pairs
- Launching our first cloud instance
- Fixing a broken instance deployment
- Terminating your instances
- Using live migration
- Working with nova-schedulers
- Creating flavors
- Defining host aggregates
- Launching instances in specific Availability Zones
- Launching instances on specific Compute hosts
- Removing Nova nodes from a cluster
- 5. Swift – OpenStack Object Storage
- Introduction
- Configuring Swift services and users in Keystone
- Installing OpenStack Object Storage services – proxy server
- Configuring OpenStack Object Storage – proxy server
- Installing OpenStack Object Storage services – storage nodes
- Configuring physical storage for use with Swift
- Configuring Object Storage replication
- Configuring OpenStack Object Storage – storage services
- Making the Object Storage rings
- Stopping and starting OpenStack Object Storage
- Setting up SSL access
- 6. Using OpenStack Object Storage
- 7. Administering OpenStack Object Storage
- 8. Cinder – OpenStack Block Storage
- 9. More OpenStack
- Introduction
- Using cloud-init to run post-installation commands
- Using cloud-config to run the post-installation configuration
- Installing OpenStack Telemetry
- Using OpenStack Telemetry to interrogate usage statistics
- Installing Neutron LBaaS
- Using Neutron LBaaS
- Configuring Neutron FWaaS
- Using Neutron FWaaS
- Installing the Heat OpenStack Orchestration service
- Using Heat to spin up instances
- 10. Using the OpenStack Dashboard
- Introduction
- Installing OpenStack Dashboard
- Using OpenStack Dashboard for key management
- Using OpenStack Dashboard to manage Neutron networks
- Using OpenStack Dashboard for security group management
- Using OpenStack Dashboard to launch instances
- Using OpenStack Dashboard to terminate instances
- Using OpenStack Dashboard to connect to instances using a VNC
- Using OpenStack Dashboard to add new tenants – projects
- Using OpenStack Dashboard for user management
- Using OpenStack Dashboard with LBaaS
- Using OpenStack Dashboard with OpenStack Orchestration
- 11. Production OpenStack
- Introduction
- Installing the MariaDB Galera cluster
- Configuring HA Proxy for the MariaDB Galera cluster
- Configuring HA Proxy for high availability
- Installing and configuring Pacemaker with Corosync
- Configuring OpenStack services with Pacemaker and Corosync
- Bonding network interfaces for redundancy
- Automating OpenStack installations using Ansible – host configuration
- Automating OpenStack installations using Ansible – Playbook configuration
- Automating OpenStack installations using Ansible – running Playbooks
- 1. Keystone – OpenStack Identity Service
- 3. Module 3
- 1. The Troubleshooting Toolkit
- 2. Troubleshooting OpenStack Identity
- 3. Troubleshooting the OpenStack Image Service
- 4. Troubleshooting OpenStack Networking
- 5. Troubleshooting OpenStack Compute
- 6. Troubleshooting OpenStack Block Storage
- 7. Troubleshooting OpenStack Object Storage
- 8. Troubleshooting the OpenStack the Orchestration Service
- 9. Troubleshooting the OpenStack Telemetry Service
- 10. OpenStack Performance, Availability, and Reliability
- A. Bibliography
- Index
OpenStack Nova supports live migration of VM-based instances between compute hosts. This is useful during maintenance and cluster balancing operations. To use live migration, you must first add a node to your Nova cluster.
Let’s assume that you have more than one host running the Nova Compute services, as described in the Configuring OpenStack Compute section. If that is not the case, you will need to configure a second host before continuing. The destination host also needs to be remotely accessible and have resources available to run the instance(s) that will be migrated.
To successfully complete live migration, both hosts must be able to communicate with each other by hostname. You can validate this by logging in to each host and pinging the other:
$ ping compute-02 PING compute-02.book (192.168.100.203) 56(84) bytes of data. 64 bytes from compute-02.book (192.168.100.203): icmp_seq=1 ttl=64 time=2.14 ms 64 bytes from compute-02.book (192.168.100.203): icmp_seq=2 ttl=64 time=0.599 ms $ ping compute-01 PING compute-01.book (192.168.100.202) 56(84) bytes of data. 64 bytes from compute-01.book (192.168.100.202): icmp_seq=1 ttl=64 time=1.29 ms 64 bytes from compute-01.book (192.168.100.202): icmp_seq=2 ttl=64 time=0.389 ms
Live migration is also dependent on the remote host having available resources for the workload. This can be done by logging into a host with the nova command-line utilities and using the following nova commands:
$ nova host-describe compute-02 +------------+------------+-----+-----------+---------+ | HOST | PROJECT | cpu | memory_mb | disk_gb | +------------+------------+-----+-----------+---------+ | compute-02 | (total) | 2 | 3107 | 37 | | compute-02 | (used_now) | 0 | 512 | 0 | | compute-02 | (used_max) | 0 | 0 | 0 | +------------+------------+-----+-----------+---------+
The first line shows the total resources available on the host. In this case, there are two vCPU, 3 GB memory, and 37 GB disk. To find out what is available on the host, subtract the values from the used_now row from the total row. In our case, the only change is that there are 512 MB of RAM in use, leaving 2.5 GB available for migrations.
If you are not already logged into a host with the Nova command-line utilities, you will need to be before proceeding. To migrate a VM-based instance between nodes, run the following commands:
export OS_TENANT_NAME=cookbook export OS_USERNAME=admin export OS_PASSWORD=openstack export OS_AUTH_URL=https://192.168.100.200:5000/v2.0/ nova live-migration --block-migrate <UUID> compute-02
Live migration is an essential feature that enables OpenStack operators and administrators to perform maintenance of the underlying cloud infrastructure without affecting the consumers of said cloud. Additionally, the OpenStack administrator can use telemetry data from Ceilometer and make live-migration decisions to balance workloads across the OpenStack cloud.
Live-migration in OpenStack is handled by the libvirt drivers. Specifically, when you issue the nova live-migration command, OpenStack compute creates a connection from libvirtd on one compute host to the same process on the remote host. Once this connection is established, depending on the parameters you specified, the memory state of the instance is synchronized and control is transferred. In our example, we specified the additional --block-migrate parameter, which handles the movement of the instance’s disk files in the absence of shared storage.
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