Nova (Compute)

Function: Manages the lifecycle of compute instances (virtual machines) in an OpenStack environment.

Key Components:

• nova-api: Accepts and responds to end user compute API calls
• nova-scheduler: Determines which compute host to run an instance on
• nova-compute: Daemon that creates and terminates VM instances via hypervisor APIs
• nova-conductor: Mediates interactions between compute nodes and database
• nova-novncproxy: Provides VNC console access to instances

Supported Hypervisors: KVM, QEMU, VMware ESXi, Hyper-V, Xen, LXC

Neutron (Networking)

Function: Provides "networking as a service" between interface devices managed by other OpenStack services.

Key Capabilities:

• Create and manage virtual networks, subnets, and routers
• Floating IP addresses for external connectivity
• Security groups for firewall rules
• Load Balancing as a Service (LBaaS)
• VPN as a Service (VPNaaS)
• Firewall as a Service (FWaaS)

Plugins: Open vSwitch, Linux Bridge, Cisco, VMware NSX, OpenDaylight

Keystone (Identity)

Function: Provides authentication, authorization, and service discovery for all OpenStack services.

Key Features:

• User authentication and token management
• Service catalog (directory of available services)
• Policy-based authorization
• Multi-tenancy support (projects/domains)
• Federation with external identity providers (LDAP, SAML, OAuth)

Authentication Methods: Password, token, LDAP, OAuth2, SAML, Kerberos

Glance (Image Service)

Function: Discovers, registers, and retrieves virtual machine images.

Key Features:

• Store and catalog VM images
• Image metadata management
• Support for multiple storage backends
• Image snapshots and cloning
• Image format conversion

Supported Formats: RAW, QCOW2, VMDK, VHD, ISO, AMI, AKI, ARI

Storage Backends: Local filesystem, Swift, Ceph RBD, S3, HTTP

Cinder (Block Storage)

Function: Provides persistent block storage to running instances (like Amazon EBS).

Key Features:

• Create, attach, and detach block volumes
• Volume snapshots and backups
• Volume cloning and extending
• Volume encryption
• Quality of Service (QoS) specifications
• Volume migration and replication

Storage Backends: Ceph RBD, LVM, NFS, iSCSI, NetApp, EMC, Pure Storage, and 70+ others

Swift (Object Storage)

Function: Scalable redundant storage system for objects and files (like Amazon S3).

Key Features:

• Store and retrieve arbitrary unstructured data
• Built-in replication and redundancy
• No single point of failure
• Scales horizontally by adding storage nodes
• RESTful HTTP API
• S3-compatible API available

Use Cases: Backups, archives, static website content, media files, VM images

Manila (Shared Filesystem)

Function: Provides shared filesystems as a service (NFS, CIFS).

Key Features:

• Create and manage shared filesystems
• Access control lists
• Snapshots and replication
• Share across multiple instances

Protocols: NFS, CIFS/SMB, GlusterFS, HDFS, CephFS

Horizon (Dashboard)

Function: Web-based user interface to OpenStack services.

Capabilities:

• Launch instances, manage networks
• Create volumes and snapshots
• Manage users, projects, and roles
• View usage statistics and quotas
• Access VM consoles via VNC/SPICE

Note: Built with Django/Python, customizable and extensible

Heat (Orchestration)

Function: Orchestration service for deploying complex cloud applications (like AWS CloudFormation).

Key Features:

• Template-based resource provisioning
• Auto-scaling groups
• Rolling updates
• Nested stacks
• AWS CloudFormation template compatibility

Template Format: HOT (Heat Orchestration Template) or CFN (CloudFormation)

Ceilometer (Telemetry)

Function: Collects measurements of cloud resource usage for monitoring, metering, and billing.

Metrics Collected:

• Instance CPU, memory, disk, network usage
• Storage consumption
• Network bandwidth
• Custom application metrics

Often paired with: Gnocchi (time-series database), Aodh (alarming service)

Ironic (Bare Metal)

Function: Provisions bare metal machines instead of virtual machines.

Use Cases:

• High-performance computing requiring direct hardware access
• Database servers needing maximum I/O
• NFV workloads requiring SR-IOV
• Workloads with software licensing tied to physical cores

Power Management: IPMI, iLO, iDRAC, Redfish

Magnum (Container Orchestration)

Function: Provides container orchestration engines (Kubernetes, Docker Swarm, Mesos) as a service.

Features:

• Deploy Kubernetes clusters on demand
• Auto-scaling cluster nodes
• Integrated with Keystone for auth
• Leverages Neutron for networking

Trove (Database as a Service)

Function: Provides relational and non-relational database engines as a service.

Supported Databases:

• MySQL, PostgreSQL, MariaDB
• MongoDB, Cassandra, Redis
• CouchDB, Percona

Features: Automated backups, replication, high availability

Barbican (Key Manager)

Function: Secure storage, provisioning, and management of secrets (passwords, keys, certificates).

Manages:

• Symmetric and asymmetric keys
• Certificates and certificate authorities
• Raw binary secrets

Backend Support: PKCS#11, KMIP, Vault, software encryption

Designate (DNS as a Service)

Function: Multi-tenant REST API for managing DNS zones and records.

Features:

• Create and manage DNS zones
• Automated record creation for instances
• Integration with multiple DNS servers

Backends: BIND9, PowerDNS, Microsoft DNS, Akamai

Octavia (Load Balancer)

Function: Load balancing as a service (successor to Neutron LBaaS).

Features:

• Layer 4 and Layer 7 load balancing
• Health monitoring
• TLS termination
• Horizontally scalable amphora-based architecture

Algorithms: Round robin, least connections, source IP