Cluster Features

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.

High Availability for Apps As a result Jelastic eliminates any risk of application downtime if one of the physical servers has any issues with performance.

Live Migration

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

Better density and a higher utilization rate is gained with a help of memory deduplication mechanism. This mechanism collects statistics to determine which files are the most frequently accessed by containers. The most commonly used files are put in cache. If a container needs to access a commonly used file, it can go straight to the cache instead of the disk. This improves performance by reducing the number of I/O operations.


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.