OpenStack Interview Questions And Answers Set-4

31. Name the commands used to pause and un-pause(resume) an instance

  • $ novaunpause INSTANCE_NAME
  • $ nova pause INSTANCE_NAME

32. List the storage locations for VM images in OpenStack

  • OpenStack Object Storage
  • Filesystem
  • S3
  • HTTP
  • RBD or Rados Block Device
  • GridFSMaster Openstack  from industry experts.

33. What is Token?

Token is a type of authentication similar to password-based validation. A token gets generated once the user inserts the credentials and authenticates as a Keystone user. The token can then be used to access OpenStack services without any revalidation. It is interesting to note that a token is active for a limited period and must be renewed after regular intervals.
To create a token, users first need to authenticate their Keystone credentials.

34. Describe the function of Filter Scheduler.

The Filter Scheduler facilitates filtering and weighting to notify where a new instance can be created. It supports working with Compute Nodes. Filter Scheduler firstly creates an unfiltered dictionary of hosts and then filter them using related properties and makes the final selection of hosts for the number of instances as needed.

35. Define the Networking option in OpenStack.

  • AvalabilityZoneFilter: filters hosts by their availability zone.
  • CapacityFilter: filtering based on volume host’s capacity consumption
  • DifferentBackendFilter: Scheduling volumes to a different back-end
  • DriverFilter: filters based on ‘filter function’ and ‘metrics’
  • InstanceLocalityFilter
  • JSONFIlter
  • RetryFilter: Filter the previously attempted hosts
  • SameBackendFilterMost in-depth, industry-led curriculum in Openstack.

36. How can an instance be paused and also unpaused?

Two types of command like $ nova pause INSTANCE_NAME and $ nova unpause INSTANCE_NAME are used to pause and unpause instances.

37. List down the Networking hardware in OpenStack.

  • Networks
  • Routers
  • Subnets
  • Ports Vendor Plugins

38. Define Hypervisor

For all cloud computing paltforms, Hypervisor is a term to define virtual machine monitor(VMM) including hardware, software and firmware components running on a virtual machine. Host machine is the one having hypervisor with one or more virtual machines.
OpenStack Compute allows multiple hypervisors. There are functionalities to choose one among them for a specific purpose.

39. List down the type of Hypervisors supported by OpenStack.

  • KVM (Kernel-based Virtual machine)
  • LXC: Linux Containers having Linux-based VMs
  • QEMU: Quick EMUlator used for development purposes
  • UML: User Mode Linux used for development purposes
  • VMware vSphere: VMware-based Linux and Windows via vCenter server connection.
  • Hyper-V: Server virtualization with Microsoft’s Hyper-V

40. Explain in brief the modular architecture of OpenStack.

The three important components of the OpenStack modular architecture are:

  • OpenStack Compute: For managing large networks on the virtual machine
  • Image Service: The delivery service provides discovery and registration for virtual disk images
  • OpenStack Object Storage: A storage system that provides support for both block storage and object storage