Managing Software Installation Using Cloudera Manager
A major function of Cloudera Manager is to install CDH and managed service software. Cloudera Manager installs software for new deployments and to upgrade existing deployments. Cloudera Manager supports two software distribution formats: packages and parcels.
A package is a binary distribution format that contains compiled code and meta-information such as a package description, version, and dependencies. Package management systems evaluate this meta-information to allow package searches, perform upgrades to a newer version, and ensure that all dependencies of a package are fulfilled. Cloudera Manager uses the native system package manager for each supported OS.
A parcel is a binary distribution format containing the program files, along with additional metadata used by Cloudera Manager. The important differences between parcels and packages are:
- Parcels are self-contained and installed in a versioned directory, which means that multiple versions of a given parcel can be installed side-by-side. You can then designate one of these installed versions as the active one. With packages, only one package can be installed at a time so there is no distinction between what is installed and what is active.
- You can install parcels at any location in the filesystem. They are installed by default in /opt/cloudera/parcels. In contrast, packages are installed in /usr/lib.
- When you install from the Parcels page, Cloudera Manager automatically downloads, distributes, and activates the correct parcel for the operating system running on each host in the cluster. All CDH hosts that make up a logical cluster need to run on the same major OS release to be covered by Cloudera Support. Cloudera Manager needs to run on the same OS release as one of the CDH clusters it manages, to be covered by Cloudera Support. The risk of issues caused by running different minor OS releases is considered lower than the risk of running different major OS releases. Cloudera recommends running the same minor release cross-cluster, because it simplifies issue tracking and supportability. You can, however, use RHEL/Centos 7.2 as the operating system for gateway hosts. See Operating System Support for Gateway Hosts (CDH 5.11 and higher only).