Monitoring

Cloud-native applications leverage cluster and container technologies, where clusters manage infrastructure, and containers handle application deployment and execution. Consequently, the monitoring targets differ from traditional applications.

Cluster Monitoring

Clusters consist of nodes, which are computing machines with CPU, GPU, Memory, and Disk, along with an operating system (OS) and container runtime for executing containers. Hence, monitoring of physical resource usage and performance necessary for container execution is done by collecting data (referred to as 'metrics' in monitoring) at the node level.

Container management is handled by Kubernetes, composed of multiple components installed on the cluster's master node. Monitoring the master node and installed components becomes necessary in case of Kubernetes failures, as container management becomes impossible. Monitoring involves tracking resource usage on the master node and the status of installed components.

Nodes and containers within a cluster communicate with each other. Monitoring network usage targets both the physical network and the logical network controlled by Kubernetes.

Application (Container) Monitoring

While cluster monitoring focuses on infrastructure resources required for container execution, container monitoring encompasses resource usage, execution status, and lifecycle monitoring. It also includes monitoring aspects such as communication volume between containers and request processing times.

Container monitoring provides metrics through the Kubernetes API and the Service Mesh API (for configuring container-to-container communication).

Notifications and Events

Notifications occur when monitoring metric data meets certain conditions defined by notification rules. These rules can be both predefined and user-defined.

Events occur when Kubernetes resources change. For instance, events are triggered by pod creation, execution, update, or deletion. Cocktail Cloud collects and provides events as notifications.

Both notifications and events provide real-time information during operation, facilitating proactive measures against application and cluster state changes and failures.

Logs

Kubernetes logs comprise three main types. Firstly, logs recorded by the Kubernetes master provide information necessary for master operation. Secondly, container logs are logs displayed on standard output (STDOUT/STDERR) during container execution. Lastly, application logs are logs recorded in separate files by containers in addition to standard output.

Cocktail Cloud collects all three types of logs, providing an environment for log retrieval and analysis.