Container Based Virtualization
Jelastic uses Parallels Cloud Server containers for supporting the largest amount of applications on a single physical server. This is achieved by using operating system-level virtualization. Container-based virtualization helps to slice hardware nodes on smaller containers and get very high density. The containers located on the Hardware Nodes are independent Linux machines on CentOS (other versions of Linux are also supported).
Container-based virtualization guarantees the highest application density and maximum utilization of server resources, resulting in the best return-on-investment for the customer. Since containers are optimized for high density environments, the customer can use larger servers for even better total cost of ownership.
Since each container is fully isolated, they are highly secure and provide maximum uptime. This isolation prevents the neighboring containers from “behaving badly”, for example stealing resources from another. Each environment with provisioned containers gets complete privacy and becomes unavailable for all other users.
High Availability for Apps
The Jelastic platform provides the highest availability by distributing containers of one environment evenly on different Hardware nodes (physical servers). This is done with the help of anti-affinity groups configured to specify that certain virtual containers should never run on the same physical server.
Jelastic has a unique feature – live migration. It allows the cluster to be rebalanced if any hardware node is overloaded. In addition, during maintenance or other planned downtime the live migration feature can perform automated evacuation of containers from a hardware node. During live migration applications keep working without downtime and get the required resources.
Jelastic’s unique vertical scaling uses live migration to ensure that applications can scale within a server without downtime. As an application scales within a server, other applications can be automatically migrated to another server to make room. Live migration allows Jelastic to deliver all the needed resources for applications without restarting containers and causing application downtime.
Density and Utilization
Jelastic’s hibernation feature delivers even better utilization of cluster resources. Optimal use of resources is achieved by suspending non-active containers and returning released resources back to the cluster.
Because they are in sleep mode, hibernated containers do not consume resources (only disk space). As a result customers save money while their containers are in hibernate mode. If applications are needed again the platform returns them to a running state again in just a few seconds.