Implementing DaemonSets
From now until the end of the chapter, we will be reviewing more niche options when it comes to running applications with specific requirements.
We'll start with DaemonSets, which are similar to ReplicaSets except that the number of replicas is fixed at one replica per node. This means that each node in the cluster will keep one replica of the application active at any time.
Important note
It's important to keep in mind that this functionality will only create one replica per node in the absence of additional Pod placement controls, such as Taints or Node Selectors, which we will cover in greater detail in Chapter 8, Pod Placement Controls.
This ends up looking like the following diagram for a typical DaemonSet:
Figure 4.3 – DaemonSet spread across three nodes
As you can see in the preceding figure, each node (represented by a box) contains one Pod of the application, as controlled by the DaemonSet...