Archive for the ‘Natty Narhwal’ Category
The OpenStack Beginner’s Guide – for Ubuntu – Natty is available in PDF format now. You can download it here:
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Nova-volume provides persistent block storage compatible with Amazon’s Elastic Block Store. The storage on the instances is non persistent in nature and hence any data that you generate and store on the file system on the first disk of the instance gets lost when the instance is terminated. You will need to use persistent volumes provided by nova-volume if you want any data generated during the life of the instance to persist after the instance is terminated.
Commands from euca2ools package can be used to manage these volumes.
Here are a few examples:
Nova Manage commands
OpenStack provides commands for administrative tasks such as user/role management, network management etc. In all the examples we will use username as “novadmin” and project name as “proj”. All the nova-manage commands will need to be run as “root”. Either run them as root or run them under sudo.
Every nova user has a role associated with him. This role can be assigned at the time of creation of the account using “nova-manage add user…” or by editing the profile later using the Openstack Dashboard by the project manager. The role can be either global or project specific in scope. All access in Openstack is governed by roles. Each role has a predefined set of operations permitted within the relevant scope(global or local)
Openstack provides ingress filtering for the instances based on the concept of security groups. OpenStack accomplishes ingress filtering by creating suitable IP Tables rules. A Security Group is a named set of rules that get applied to the incoming packets for the instances. You can specify a security group while launching an instance. Each security group can have multiple rules associated with it. Each rule specifies the source IP/network, protocol type, destination ports etc. Any packet matching these parameters specified in a rule is allowed in. Rest of the packets are blocked.
In OpenStack, the networking is managed by a component called “nova-network”. This interacts with nova-compute to ensure that the instances have the right kind of networking setup for them to communicate among themselves as well as with the outside world. Just as in Eucalyptus or AWS, each OpenStack instance can have 2 IP addresses attached to it. One is the private IP address and the other called Public IP address. The private IP address is typically used for communication between instances and the public IP is used for communication of instances with the outside world. The so called public IP address need not be a public IP address routable on the Internet ; it can even be an address on the corporate LAN.
Cloud computing is a computing model, where resources such as computing power, storage, network and software are abstracted and provided as services on the Internet in a remotely accessible fashion. Billing models for these services are generally similar to the ones adopted for public utilities. On-demand availability, ease of provisioning, dynamic and virtually infinite scalability are some of the key attributes of cloud computing.
An infrastructure setup using the cloud computing model is generally referred to as the “cloud”. The following are the broad categories of services available on the cloud:
- Infrastructure As A Service (IAAS)
- Platform As A Service (PAAS)
- Software As A Service (SAAS)
Amazon Web Services (AWS) is one of the major players providing IAAS. They have two popular services – Elastic Compute Cloud (EC2) and Simple Storage Service (S3). These services are available through web services.