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How OpenStack works?

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How OpenStack works?
posted Aug 19, 2016 by anonymous

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1 Answer

+1 vote

OpenStack is an IaaS cloud computing project that is free open-source software.

Its mission is to provide a flexible solution for both public and private clouds of any size, and for this matter two basic requirements are considered: clouds must be simple to implement and massively scalable.

To meet these principles OpenStack is divided into different components that work together. This integration is achieved through application programming interfaces – APIs – offered and consumed by each service.

With these APIs, services can communicate with each other and also allows a service to be replaced by another with similar characteristics, only if the form of communication is respected. That is, OpenStack is extensible and meets the needs of those who wish to implement it.

Structure of OpenStack
enter image description here

This is a simplified view of the architecture, assuming that all the services are used in the most standard configuration. Nor illustrates how the cloud consumers can interact with it.

Following components can be seen on the graph

  • “Horizon” Dashboard provides an end user and administrator interface to other services. It is the service I’m currently working ;)
  • “Nova” Compute retrieves images and associated metadata, and transforms user requests on virtual machines.
  • “Neutron” Network provides virtual networks as a service between devices managed by other OpenStack services, such as a virtual machine from Nova. Allows users to create their own networks and then link them to the devices of their choice.
  • “Cinder” Block Storage provides persistent storage for VMs hosted on the cloud.
  • “Glance” Image provides a catalog and a repository for images.
  • “Swift” Object Store provides object storage. This is not a file system, is more like a container that can store files and retrieve them later.
  • “Keystone” Identity provides authentication and authorization for all OpenStack services, and a catalog of these services of a particular cloud.

OpenStack Software Diagram
enter image description here

Ref: http://vmartinezdelacruz.com/in-a-nutshell-how-openstack-works/

answer Aug 20, 2016 by Salil Agrawal
Nicely explained. Can you please tell me what is the difference between "Swift" and "Cinder". In the other words, I want to know the difference between block storage and object storage. Any day to day activity would be the best example to differentiate between them, Thanks in advance.
Swift provides the service to store data in remote location and can be accessed through URL while cinder is used to store data in file system. Using block storage a file can be shared among multiple VMs.
Similar Questions
+1 vote

When I used mysql as the keystone's backend in openstack, iI found that the 'token' table saved 29 millions record (using myisam as engine,the size of token.MYD is 100G) and have 4 new token save per second. That result to the slow query of a token .since of inserting new token frequently, how could I set the configure to speed up the query operation.

the token's struct is id,expires,extra,valid,user_id with index {expires,valid}
and the select sql is select id,expires,extra,valid,user_id from token where valid=1 and expires >='XXXX-XX-XX XX:XX:XX' and user_id ='XXXXXXXXXXXXXXXXXXX';with often return 2 results.

Here is some db status data in a real openstack environment with 381 active VMs:

+-----------------------+-------------+ 
| Variable_name | Value | 
+-----------------------+-------------+ 
| Handler_read_first | 259573419 | 
| Handler_read_key | ********** | 
| Handler_read_next | ********** | 
| Handler_read_prev | 1235 | 
| Handler_read_rnd | 1951101 | 
| Handler_read_rnd_next | ********** | 
+-----------------------+-------------+ 

and

+-------------------------+------------+ 
| Variable_name | Value | 
+-------------------------+------------+ 
| Qcache_free_blocks | 498 | 
| Qcache_free_memory | 1192512 | 
| Qcache_hits | ********** | 
| Qcache_inserts | 352700155 | 
| Qcache_lowmem_prunes | 34145019 | 
| Qcache_not_cached | ********** | 
| Qcache_queries_in_cache | 1681 | 
| Qcache_total_blocks | 4949 | 
+-------------------------+------------+

it seems that the 'insert' operation of saving new token affects the query buffer,and result of a low-level of query-hit's rate.

Please help me?

+2 votes

What is the difference between:

  1. using "the Command-line interface to the OpenStack APIs" through the command "openstack"
    and
  2. using the separate APIs of the different components (for example using the command-line interface to the Neutron APIs directly)?

Advantages and disadvantages?

+2 votes

I configured nova.conf file with:
cpu_allocation_ratio=16.0
ram_allocation_ratio=1.5
specifying CoreFilter in scheduler_default_filters.
After this configuration i can't see the overcommitment results in the CLI or in Horizon.
Why? Any tips?

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