Merge branch 'release_notes_6.8.1' into 'master'

Release notes for ARC 6.8.1

See merge request nordugrid/arc!1059

release_notes/release_notes_6.8.1

+Advanced Resource Connector (ARC)
+=================================
+
+
+Release Notes for NorduGrid ARC  6.8.1     08.10.2020
+------------------------------------------------------
+
+This is an express release which targets purely the arc.conf changes related to the 
+deprecated arc.conf values in ARC 6.8.0 
+
+In ARC 6.8.0 the ARC validator would prevent ARC from starting up if any of the 
+deprecated blocks and options were present in arc.conf. From 6.8.1 ARC will start 
+even with the deprecated options in place. Note however that they are still 
+deprecated and should be removed. The options will have no effect to your running
+instance of ARC, thus of no value. 
+ 
+The deprecated arc.conf values in ARC  6.8.0 are
+-------------------------------------------------
+
+* In the [arex/jura] block:
+  * urdelivery_keepfailed (in [arex/jura] block)
+* In the [arex/jura/sgas:targetname] block:
+  * legacy_fallback
+* In the [arex/jura/apel:targetname] block:
+  * use_ssl
+  * benchmark_type
+  * benchmark_value
+  * benchmark_description
+  * legacy_fallback
+* [arex/jura/archiving] block (the whole block is deprecated)
+  * archivedir
+  * logfile
+  * archivettl   
+
+
+For all the other changes included in 6.8.0, please refer to the release notes: 
+http://www.nordugrid.org/arc/releases/6.8/release_notes_6.8.html
+
+Important note on xrootd version for sites using the nordugrid-arc-plugins-xrootd package
+------------------------------------------------------------------------------------------
+For sites who install the nordugrid-arc-plugins-xrootd package note that ARC 6.8.0 is built with xrootd 5.
+On the date of the release xrootd 5 has not yet reached EPEL-stable which means that to install(update) ARC 6.8.0 on RHEL-systems,
+you must enable the epel-testing repo: 
+yum install(update) "nordugrid-arc*" --enablerepo=epel-testing
+or alternatively install xrootd 5 before updating ARC. 
+
+
+Documentation
+==============
+The ARC 6 documentation can be found at http://www.nordugrid.org/arc/arc6
+
+If you miss something or have questions, please contact us!
+
+
+Installing ARC 6 
+=================
+We recommend to install ARC release using the Nordugrid repository.
+* Start with the basics: http://www.nordugrid.org/arc/arc6/admins/try_arc6.html
+* Get production ready: http://www.nordugrid.org/arc/arc6/admins/arc6_install_guide.html 
+
+Note that if you instead install from EPEL for RHEL 7 compatible systems,
+the ARC 6 packages can be found as nordugrid-arc6-* and not nordugrid-arc-*
+This was needed in order to supply both ARC 5 already available for RHEL7 and the new ARC 6.
+
+
+We provide binary builds for all supported versions of
+  * Debian (i386 and amd64)
+  * Fedora (i386 and x86_64) - from Fedora 26 - no i386 support
+  * CentOS EL6 (i386 and x86_64) and EL7/EL8 (x86_64) - from EL7 no i386 support
+  * Ubuntu (i386 and amd64, both LTS and interim releases) - from Ubuntu 20.04 no i386 support
+
+In addition we build nightly packages for older platforms. 
+
+Future support of ARC 5-series
+===============================
+As of June 2020 no more security updates are provided to ARC 5.
+Also since the release of ARC 6 in June 2019, no more development on the ARC 5 code base has been provided.
+
+Production Sites already running ARC 5 will still get operational site support in form of
+deployment and configuration troubleshooting help via GGUS until end June 2021.
+However, we may recommend upgrading to ARC 6 depending on the issues the site is facing. 
+
+ARC5 is available in EPEL7 and will stay there. EPEL8 will only contain ARC 6.
+To install ARC 6 from EPEL7 the package-names are of type: nordugrid-arc6-* 
+
+
+Getting in touch
+==================
+If you need help with the configuration file or have any other questions related to ARC 6, please contact us via
+* Email: nordugrid-discuss@nordugrid.org or wlcg-arc-ce-discuss@cern.ch
+* Skype channel dedicated to ARC 6 support: https://join.skype.com/dyf3A6Uutjy2
+
+
+Known issues
+==============
+* For sites with nordugrid-plugins-xrootd installed epel-testing repo must be enabled, otherwise update will fail. 
+  This is because at the time of the 6.8.0 release  the xrootd 5 had not  yet reached epel-stable, and ARC is built
+  with xrootd 5. 
+* In Centos8 the openldap server is not installable because slapd is not available in the RHEL8 release (Bugzilla 3944).
+  As a consequence, the LDAP-based server-side information system interface of the ARC-CE will not be available either.
+  If interaction with the ARC-CE relies on LDAP-based information schemas (glue1.3 or nordugrid schema),
+  then we recommend that you stay with Centos7 for the time being.
+* Related to the new accounting system introduded in release 6.4.0: 
+** Accounting records created by ARC 6.4.0 are affected by a bug causing missing benchmark values:
+   https://bugzilla.nordugrid.org./show_bug.cgi?id=3921#c3
+   Recommendations are to update to a newer version of ARC.
+   The bugreport gives instructions on how to manually fix the wrong benchmark values.
+ 
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