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 cloud hosts. By default, container images are built on the seed. Typically the seed host is deployed as a VM but this is not mandatory.
- 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 Cloud hosts.
- Cloud hosts
The cloud hosts run the OpenStack control plane, network, monitoring, storage, and virtualised compute services. Typically the cloud hosts run on bare metal but this is not mandatory.
- Bare metal compute hosts
In a cloud providing bare metal compute 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.
In many cases the control and seed host will be the same, although this is not mandatory.
Cloud hosts can further be divided into subclasses.
Controller hosts run the OpenStack control plane services.
Network hosts run the neutron networking services and load balancers for the OpenStack API services.
Monitoring host run the control plane and workload monitoring services. Currently, kayobe does not deploy any services onto monitoring hosts.
- Virtualised compute hypervisors
Virtualised compute hypervisors run the tenant Virtual Machines (VMs) and associated OpenStack services for compute, networking and storage.
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 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 cloud 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 cloud hosts to provision the bare metal compute hosts.
- Internal network
The internal network hosts the internal and admin 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.