Issue with the Snappy package when trying to install an Hadoop DataNode using Apache Ambari

During an Hadoop cluster installation on Red Hat/CentOS using Apache Ambari (https://ambari.apache.org/), a DataNode could fail to install with the following error:

resource_management.core.exceptions.Fail: Execution of '/usr/bin/yum -d 0 -e 0 -y install snappy-devel' returned 1. Error: Package: snappy-devel-1.0.5-1.el6.x86_64 (HDP-UTILS-1.1.0.20)
           Requires: snappy(x86-64) = 1.0.5-1.el6
           Installed: snappy-1.1.0-1.el6.x86_64 (@ftp3-updates)
               snappy(x86-64) = 1.1.0-1.el6
           Available: snappy-1.0.5-1.el6.x86_64 (HDP-UTILS-1.1.0.20)
               snappy(x86-64) = 1.0.5-1.el6
You could try using --skip-broken to work around the problem
You could try running: rpm -Va --nofiles --nodigest

The root cause here is the following: Hadoop requires a version of the snappy-devel package that is a lower one of that already present on the machine. In order to fix the problem you have to connect to the host and execute the following commands from a shell:

yum remove snappy
yum install snappy-devel

and then retry the installation. It could have been nicer to have this error managed by the Ambari Python script itself rather than requiring a manual intervention. This issue has been reported for Ambari 2.1.0, but it is still present in the latest (2.2.0).

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