Architecture¶
Hosts in the System¶
In a system deployed by Kayobe we define a number of classes of hosts.
- Ansible control host
The Ansible control host is the host on which kayobe, kolla and kolla-ansible will be installed, and is typically where the cloud will be managed from.
- Seed host
The seed host runs the bifrost deploy container and is used to provision the overcloud hosts. By default, container images are built on the seed. Typically the seed host is deployed as a VM but this is not mandatory.
- Seed hypervisor host
The seed hypervisor host is configured with Libvirt and KVM. It hosts the seed VM (when the seed host is deployed as a VM) and infrastructure VMs.
- Infrastructure VM hosts
Infrastructure VMs (or Infra VMs) are virtual machines that may be deployed to provide supplementary infrastructure services. They may be for things like proxies or DNS servers that are dependencies of the overcloud hosts.
- Overcloud hosts
The overcloud hosts run the OpenStack control plane, network, monitoring, storage, and virtualised compute services. Typically the overcloud hosts run on bare metal, but this is not mandatory.
- Bare metal workload hosts
In a cloud providing bare metal workload services to tenants via ironic, these hosts will run the bare metal tenant workloads. In a cloud with only virtualised compute this category of hosts does not exist.
Note
In many cases the Ansible control host and seed hypervisor will be the same, although this is not mandatory.
Overcloud Hosts¶
Overcloud hosts can further be divided into subclasses.
- Controllers
Controller hosts run the OpenStack control plane services.
- Network
Network hosts run the neutron networking services and load balancers for the OpenStack API services.
- Monitoring
Monitoring hosts run the control plane monitoring services.
- Storage
Storage hosts run the storage services.
- Virtualised compute hypervisors
Virtualised compute hypervisors run the tenant Virtual Machines (VMs) and associated OpenStack services for compute, networking and storage.
Networks¶
Kayobe’s network configuration is very flexible but does define a few default classes of networks. These are logical networks and may map to one or more physical networks in the system.
- Overcloud admin network
The overcloud admin network is used to access the hosts in the system for administrative purposes, e.g. for remote SSH access.
- Overcloud out-of-band network
Name of the network used by the seed to access the out-of-band management controllers of the bare metal overcloud hosts.
- Overcloud provisioning network
The overcloud provisioning network is used by the seed host to provision the overcloud hosts.
- Workload out-of-band network
Name of the network used by the overcloud hosts to access the out-of-band management controllers of the bare metal workload hosts.
- Workload provisioning network
The workload provisioning network is used by the overcloud hosts to provision the bare metal workload hosts.
- Cleaning network
The cleaning network is used by the overcloud hosts to perform cleaning on the bare metal workload hosts.
- Inspection network
The inspection network is used by the overcloud hosts to perform hardware introspection on the bare metal workload hosts.
- Internal network
The internal network hosts the internal OpenStack API endpoints.
- Public network
The public network hosts the public OpenStack API endpoints.
- External network
The external network provides external network access for the hosts in the system.
- Tunnel network
The tunnel network carries tenant overlay network traffic.
- Storage network
The storage network carries storage data traffic.
- Storage management network
The storage management network carries storage management traffic.
