Several concepts of OpenStack

The recent deployment of OpenStack involves a number of concepts between the various services, briefly documenting some of them as memos.

Services (Service)

In OpenStack, a service has several endpoints through which the user accesses the service and uses the functionality provided by the service;

Compute Services (Compute service)- Nova

Network Services (Networking service)--neutron

Identity Service--keystone

Image Service--glance

Interface Services (Dashboard)--horizon

Block Storage (blocks Storage)--cinder

Object Storage Service (Storage)--swift

Orchestration Service (Orchestration)--heat

Monitoring Services (Telemetry)--ceilometer

Data processing service (data processing)--sahara

Database service--trove

An integrated project, provide scalable and reliable Cloud Database-as-a-service functionality for both relational and Non-relational database engines.

Comprehensive

Restful

Using RESTful Web Services api,representational state Transfer (rest, representational status transfer) is a widely used hypermedia architecture style in the World Wide web;

Network time Protocol (NTP)

Network Time protocol, which can obtain time from a more precise time source, using NTP in OpenStack to ensure time synchronization between each physical node

Message Broker

Software that provides AMQP messaging functionality within the Compute service, default to RabbitMQ

Message Queuing (Messages queue)

Pass the client's request to the appropriate worker process, and return the result to the client after the task has finished executing

Load Balancer (balancer)

A load balancer is a logical device, belongs to a cloud account. It is used to distribute workloads between multiple back-end systems or services, based on the criteria defined as part of its configuration.

Store

ISCSI

The SCSI disk protocol tunneled within Ethernet, supported by Compute, Object Storage, and Image Service.

Xfs

64-bit file system developed by Silicon Graphics, longer than processing parallel I/O operations and maintaining data consistency

Extended Properties (Extended attributes (xattr))

File system option that enables storage of additional information beyond owner, group, permissions, modification time, and So on. The underlying Object Storage file system must support extended attributes.

Logical Volume Manager (LVM)

Provides a method of allocating space on mass-storage devices that's more flexible than conventional partitioning schemes .

Calculation

Virtual Machine (VM)

An operating system instance running on a virtual machine monitor that can run multiple virtual machines concurrently on a physical host

Virtual Machine Monitor (hypervisor)

Manage and control virtual machine access to the underlying hardware

kernel-based VM (KVM)

An openstack-supported hypervisor. KVM is a full virtualization solution for Linux on x86 hardware containing virtualization extensions (Intel VT or amd-v), ARM, IBM Power, and IBM zSeries. It consists of a loadable kernel module, that provides the core virtualization infrastructure and a processor specific mod Ule.

Quick EMUlator (QEMU)

QEMU is a generic and open source machine emulator and Virtualizer.

One of the hypervisors supported by OpenStack, generally used for development purposes.

Virtual machine instance (instance)

A virtual machine that is running or in a known state

Cirros

Small Linux systems for testing cloud environments

Internet

External networks (external network)

Manage networks (Management Network)

Network segment for management, connectivity to all physical nodes, extranet inaccessible

Instance tunneling Networks (instance Tunnels network)

Network segment for virtual machine instance traffic between compute nodes and network nodes

DHCP proxy (DHCP agent)

Network proxy that provides DHCP services for virtual networks in OpenStack

Third tier agent (L3 agent)

Network proxy for a third tier (routing) service in OpenStack for virtual networks

Security group

A set of network filtering rules applied to compute instances

Dnsmasq

A background process that provides DNS, DHCP, BOOTP, and TFTP services for a virtual network

Flat Network

Virtual network type that uses neither VLANs nor tunnels to segregate tenant traffic. Each flat network typically requires a separate underlying physical interface defined by bridge mappings. However, a flat network can contain multiple subnets.

Floating IP Address

An IP address, a project can associate with a VM so that the instance have the same public IP address each time the IT Boots. You create a pool of floating IPs addresses and assign them to instances as they is launched to maintain a consistent IP a ddress for maintaining DNS assignment.

Generic receive offload (GRO)

Feature of certain network interface drivers that combines many smaller received packets into a large packet before delive Ry to the kernel IP stack.

Generic Routing Encapsulation (GRE)

A protocol that encapsulates several network layer protocols in a virtual point-to-point connection

Ipset

Extension to iptables This allows creation of firewall rules that match entire "sets" of IP addresses simultaneously. These sets reside in indexed data structures to increase efficiency, particularly on systems with a large quantity of rule S.

Iptables

Used along with Arptables and Ebtables, iptables create firewalls in Compute. Iptables is the tables provided by the Linux kernel firewall (implemented as different netfilter modules) and th E chains and rules it stores. Different kernel modules and programs is currently used for Different Protocols:iptables applies to IPv4, Ip6tables to I PV6, Arptables to ARP, and ebtables to Ethernet frames. Requires root privilege to manipulate.

Network namespace

Linux kernel feature that provides independent virtual networking instances on a single host with separate routing tables and interfaces. Similar to virtual Routing and forwarding (VRF) services on physical network equipment.

Network Address Translation (NAT)

The process of modifying IP address information while in transit. Supported by Compute and Networking.

Virtual Networking

A generic term for virtualization of network functions such as switching, routing, load balancing, and security using a CO Mbination of VMs and overlays on physical network infrastructure.

Virtual Network Computing (VNC)

Open source GUI and CLI tools used for remote console access to VMs. Supported by Compute.

Jumbo Frame

Feature in modern Ethernet networks, supports frames up to approximately 9000 bytes.

Maximum Transmission Unit (MTU)

Maximum frame or packet size for a particular network medium. Typically bytes for Ethernet networks.

Metadata Agent

OpenStack Networking Agent that provides metadata services for instances.

Open VSwitch

Open VSwitch is a production quality, multilayer Virtual Switch licensed under the Open Source Apache 2.0 license. It is designed to enable massive network automation through programmatic extension, while still supporting standard manage ment interfaces and protocols (for example NetFlow, SFlow, SPAN, RSPAN, CLI, LACP, 802.1ag).

Path MTU Discovery (PMTUD)

Mechanism in IP networks to detect end-to-end MTU and adjust packet size accordingly.

Plug-in

Software component providing the actual implementation for Networking APIs, or for Compute APIs, depending on the context.

Promiscuous mode (promiscuous)

Causes the network interface to pass all traffic it receives to the host rather than passing only the frames addressed to It.

Multi-host

High-availability mode for Legacy (Nova) networking. Each compute node handles NAT and DHCP and acts as a gateway for all of the VMs on it. A networking failure on one compute node doesn ' t affect VMs on other compute nodes.

Icmp

Internet control Message Protocol, used by the network devices for Control messages. For example, ping the uses ICMP to test connectivity.

Virtual Private Network (VPN)

Provided by Compute in the form of cloudpipes, specialized instances that is used to create VPNs on a per-project basis.

Several concepts of OpenStack