Namespaces create an abstraction of global system resources that resembles these virtual resources inside the namespace appear to be global. Any system changes sources inside the namespace are not noticeable outside of the namespace. As can be seen from the previous one chapters ing online, namespaces are used as implementations of linux containers.
There are six types of namespace in Linux using ing online:
∙ User spaces,
Process areas (PID),
∙ spaces for inter-communications communication (IPC),
∙ network spaces, ∙ root directory spaces,
∙ Domain Namespace (UTS).
User namespace isolates security identifiers and attributes such as such as user and group identifiers, keys, and permissions. These identifiers and parameters may be different ing online for one process in different user namespaces. This in practice means that the process can run in one user space with the rights of a standard user and in another space with administrative rights.
Processes are separated by process identifiers (PIDs). That is, different processes may have the same identifier in separate process areas. Process identifiers within each process area start from number 1 and new processes are created inside ing online of the same name for the system called the fork, as is the case at the start operating system of the Unix type. Process identifiers are unique within the process namespace.
Intermediate Communication Names (IPC) separates inter-process communication resources, primarily IPC System V objects and posix message queues. In each IPC space, these objects use a different way of identifying than the file system path.
Network namespaces isolate sources related to network communications such as network interfaces, IPv4 and IPv6 protocols, routing tables, firewalls, network directories, sockets, and so on. Each physical network interface can only belong to one network namespace. For communication ing online between network namespaces, virtual pairs can be used network interfaces that create virtual network tunnels between these namespaces.
As a result, these tunnels behave like physical cable lines. After removing the network namespace, its physical interfaces are moved to the default network namespace. Processes within the different root directory namespaces see a different directory hierarchy of the file system. Named domain names ing online are provided isolation of two system identifiers: guest name and domain name NIS. It follows ing online that the domain name of the host is in the different namespace of the UTS different.
Cloud computing is still a fairly new concept in IT, and has only begun to be used in 2007. It is a model that makes it ubiquitous, reliable and simple access to shared, fully configurable ing online computing resources, such as: servers, storage devices, networks, applications or services.
∙ Computing resources on request:
The user is able to provide the required computing resources for himself without having to interact with the service provider.
∙ Access via Network:
All of the resources are available via a computer network and can be easily managed via standard web-based or desktop applications or program interfaces.
The Cloud Poster typically has some sources prepared in advance. These are dynamically allocated and removed to junk users according to the current need.
∙ Dynamic scaling:
This is an automatic expansion or decrease of the currently allocated resources
based on their immediate expense.
∙ Measurable services:
The extent and utilization of the resources used are monitored and these results are provided to users and providers for example for accounting or information purposes.
∙ Software as a Service (SaaS):
Ability to provide a user created by a provider running on his / hers cloud infrastructure. Applications can be accessed from different devices either through a web browser or application program interface.
Platform as a Service (PaaS):
Ability to provide a user with the environment for their applications. The customer does not manage lower layers of cloud infrastructure, such as a network, servers, or storage, but only set to host their applications.
∙ Infrastructure as a Service (IaaS):
The ability to provide computing power, storage, network and other resources to the user, where the user is able to run their software.