Most VMware admins are familiar with the idea of namespaces when using the
Let me explain the difference.
In VMware the
Each namespace includes a set of subcommands used to perform specific tasks. For example, the most commonly used namespace is
vim-cmd command but it is important to understand that this concept is very different from how namespaces work in OpenShift and Kubernetes. Let me explain the difference.
In VMware the
vim-cmd utility gives you a CLI interface to manage different parts of the ESXi host and its components. It organizes commands into namespaces, which group together related functions for things like managing virtual machines, storage, networking, etc.Each namespace includes a set of subcommands used to perform specific tasks. For example, the most commonly used namespace is
vmsvc, which handles VM operations but there are more namespaces for managing services, host settings, datastores, etc. A simple list when running "vim-cmd help" shows that are about 20 or so namespaces when managing a VMware ESXi host.Here are a few of the key
vim-cmd namespaces you’ll typically use on ESXi and what they’re for:
- vmsvc – Virtual Machine Service
The vmsvc namespace is used to manage virtual machines (VMs) on the ESXi host. It provides commands for starting, stopping, getting information, and other VM operations.
Example Commands :
vim-cmd vmsvc/getallvms: List all VMs on the host. - hostsvc – Host Service
The hostsvc namespace is used to manage the ESXi host itself. This includes operations related to the host's services, networking, and maintenance tasks.
Example Commands :
vim-cmd hostsvc/maintenance_mode_enter: Put the ESXi host into maintenance mode. - datastore – Datastore and file Operations
The datastore namespace manages the datastores (storage) on the ESXi host, including listing, mounting, unmounting, and querying information about datastores.
Example Commands:vim-cmd datastore/lists: List all datastores on the host. - settings – ESXi Host Settings Management
The settings namespace deals with configuring and managing the system settings on the ESXi host.
Example Commands:vim-cmdsettings/user/add : Add a new user to the ESXi host.
In OpenShift, a namespace is very different.
It is a way to keep things organized and separate inside the same Openshift cluster. It is a built-in Kubernetes feature. OpenShift calls these namespaces projects, but they work the same way. They help group related resources together so things don’t get mixed up.
An OpenShift namespace is conceptually similar to a vCenter folder but with built-in RBAC, resource quotas, and policy enforcement. An importand difference is that vCenter folders can be nested to form a hierarchy while OpenShift namespaces are flat.
An OpenShift namespace is conceptually similar to a vCenter folder but with built-in RBAC, resource quotas, and policy enforcement. An importand difference is that vCenter folders can be nested to form a hierarchy while OpenShift namespaces are flat.
Right after an OpenShift 4 cluster is installed a number of system namespaces are created for platform operators, networking, monitoring, and core services. You can run the command "oc get namespaces" which will list all the namespaces created initially for you. You will notice that are about 50-70 namespaces created initially depending on the platform you are on ( AWS, Azure, etc ), depending on the installation method used ( IPI vs UPI ) and the number of operators that were initially installed. We could categorize these namespaces in core system, operator and component, networking, authorization and monitoring.
- openshift – Core OpenShift resources (templates, global config)
- kube-system – Kubernetes system services (like DNS, kube-proxy)
- kube-node-lease – Heartbeat mechanism for node liveness detection
- openshift-apiserver – OpenShift API server deployment
- openshift-etcd – Manages etcd pods, certificates, and configs
- openshift-machine-api – Manages nodes and Machines (e.g., in IPI/cloud setups)
- openshift-monitoring – Manages Prometheus, Alertmanager, Thanos, Grafana
- openshift-ingress-operator - Manages ingress routers
- openshift-cluster-version - Manages Cluster Version Operator
- openshift-authentication - Manages OAuth identity providers
- openshift-config - Manages Cluster-wide configuration (e.g., proxy, IDPs)
