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Running a pre-check

Unravel provides a utility,, to make sure your Unravel host meets Unravel's requirements.

  • On your Unravel host, it checks:

    • User, memory, free space, and dependency issues.

    • If you're using Kerberos, it checks for tooling and keytab issues.

    • That the Unravel host is an edge node.

  • On your Hadoop setup, it confirms that the Unravel host is an edge node, and checks for service access issues.

To run this utility, follow the steps below.

  1. Download the Precheck utility.

  2. On the Unravel host, uncompress unravel-precheck-latest-tar.gz.

    tar zxvf unravel-precheck-latest.tar.gz

    Uncompressing the archive results in a directory named unravel-precheck that contains two scripts, and

  3. To configure, run unravel-precheck/ This launches a menu-driven interface for changing various settings.



    If you're doing a pre-upgrade check, run to import your settings from

  4. Run as root.

    ./unravel-precheck/ [--no-kerberos]




    Disables Kerberos checks.

    Sample output
    [root@node14 ~]# ./unravel-precheck/ --no-kerberos
    INFO  *** Parsing (--no-kerberos): --no-kerberos with no value
    Unravel verification tool, ran on 2019-08-14 00:11:25 UTC
    | host
    |  run-as-root                   Ok
    |  os                            Ok              CentOS 7.6
    |  libaio                        ERROR           Not installed
    |  directory                     Info            data: doesn't exists, software: doesn't exists
    |  free-space                    Ok              data: 1650G, software: 1650G
    |  memory                        Ok              125G
    |  cpu                           Ok              x86_64, 144 cores
    |  ports                         Ok
    |  ntp                           ERROR           ntpstat missing
    |  max-map-count                 Ok              262144
    |  selinux                       Ok              Not installed
    |  unravel-service-account       ERROR           Not found
    |  unravel-service-group         Skipped         Prerequisite test errored
    |  dependencies                  ERROR           Missing 2 out of 69 programs
    |  tmp-exec                      Ok
    |  ondemand-dependencies         ERROR           Missing 6 out of 10 libraries
    | kerberos
    |  kerberos-tools                Skipped         Test disabled
    |  check-keytab                  Skipped         Test disabled
    | hadoop
    |  hadoop-tools                  Ok
    |  check-distribution            Ok              HDP 2.6.5
    |  cluster-manager               Skipped         Missing configuration
    |  hdfs-access                   Skipped         Prerequisite test errored
    |  yarn-access                   Skipped         Prerequisite test errored
    |  yarn-rm-webapp                Skipped         Missing configuration
    |  yarn-ats                      Skipped         Prerequisite test errored
    |  hive-tools                    Ok
    | Checks completed
    |  Successful : 13
    |  Skipped    : 8
    |  Error      : 5
    |  Total      : 26
    See report: ./unravel-precheck/results/20190814-001125/report.txt
    Missing dependencies (./unravel-precheck/results/20190814-001125/missing.dependencies) :
    - rdate
    - zip
    Missing ondemand dependencies (./unravel-precheck/results/20190814-001125/missing.ondemand.dependencies) :
    - cyrus-sasl-devel
    - cyrus-sasl-gssapi
    - cyrus-sasl-plain
    - python-saslwrapper
    - saslwrapper
    - saslwrapper-devel
    [root@node14 ~]#
  5. Check the results for problems.

    The script outputs the checks/tests ran and their result. Next it lists all missing "general" dependencies and finally missing OnDemand dependencies. The possible test status are:

    • Ok

    • Info: Some information you might want to know.

    • Skipped: A particular test was skipped because:

      • Disabled: The test was manually disabled.

      • Missing configuration: You need to run first.

      • Prerequisite test errored: Some other test didn't run successfully, so this test was skipped.

    • ERROR: The test failed. To see why, look at the detailed report, unravel-precheck/results/YYYYMMDD-HHMISS/report.txt

    Three reports (text files) located in ./unravel-precheck/results/YYYYMMDD-HHMISS/

    Report Name



    Detailed information on the test results. Check this file if any of the checks didn't complete with a status of OK.


    Missing general dependencies.


    Missing dependencies for OnDemand.