DHCPv6 lease not released at VM deletion opearion

Solution Verified - Updated -

Environment

  • Red Hat OpenStack Version 10

Issue

  • dhcp6_release is unable to clean IPv6 entries from DHCP lease during VM delete operation in RHOSP 10 environment.

    # cat /var/lib/neutron/dhcp/0c3af617-acd3-4bd3-86d2-7cdba82893c5/leases
duid xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx
1518436189 1055540937 xxxx:xxxx:xxxx:xxx::xx host-xxxx-xxxx-xxxx-xxx--xx xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx

Resolution

  • The RFE has raised to the engineering team for backporting.

Root Cause

  • In RHOS10, the rpm dnsmasq-utils-2.66-21.el7.x86_64 does not have dhcp6_release binary which is the root cause of the issue.

    @overcloud-controller-0 ~]# cat /etc/redhat-release;rpm -ql dnsmasq-utils-2.66-21.el7.x86_64
Red Hat Enterprise Linux Server release 7.4 (Maipo)
/usr/bin/dhcp_lease_time
/usr/bin/dhcp_release
/usr/share/man/man1/dhcp_lease_time.1.gz
/usr/share/man/man1/dhcp_release.1.gz

  • Currently the dhcp6_release binary is belongs to dnsmasq-utils-2.76-2.el7_4.2.x86_64 package which is avaible in RHOSP12 repository.

    # rpm -ql dnsmasq-utils-2.76-2.el7_4.2.x86_64
/usr/bin/dhcp_lease_time
/usr/bin/dhcp_release
/usr/bin/dhcp_release6
/usr/share/man/man1/dhcp_lease_time.1.gz
/usr/share/man/man1/dhcp_release.1.gz
/usr/share/man/man1/dhcp_release6.1.gz

# yum info dnsmasq-utils-2.76-2.el7_4.2.x86_64
Loaded plugins: product-id, search-disabled-repos, subscription-manager
Installed Packages
Name        : dnsmasq-utils
Arch        : x86_64
Version     : 2.76
Release     : 2.el7_4.2
Size        : 39 k
Repo        : installed
From repo   : rhel-7-server-openstack-12-rpms
Summary     : Utilities for manipulating DHCP server leases
URL         : http://www.thekelleys.org.uk/dnsmasq/
License     : GPLv2 or GPLv3
Description : Utilities that use the standard DHCP protocol to
            : query/remove a DHCP server's leases.

Diagnostic Steps

  • Verify the dhcp-agent.log, which threw the exception that dhcp_release6 is not present on this system.

    2018-02-12 08:28:58.306 97074 DEBUG neutron.agent.linux.utils [req-ef61cc7b-5e3b-4e9d-b942-65246f63a126 9e16ad0a563d436e9f83533773c19e14 5f1b1e40249641ac9c96cf779b60119c - - -] Running command: ['env', 'LC_ALL=C', 'dhcp_release6', '--help'] create_process /usr/lib/python2.7/site-packages/neutron/agent/linux/utils.py:89
2018-02-12 08:28:58.313 97074 ERROR neutron.agent.linux.utils [req-ef61cc7b-5e3b-4e9d-b942-65246f63a126 9e16ad0a563d436e9f83533773c19e14 5f1b1e40249641ac9c96cf779b60119c - - -] Exit code: 127; Stdin: ; Stdout: ; Stderr: env: dhcp_release6: No such file or directory
2018-02-12 08:28:58.314 97074 DEBUG neutron.cmd.sanity.checks [req-ef61cc7b-5e3b-4e9d-b942-65246f63a126 9e16ad0a563d436e9f83533773c19e14 5f1b1e40249641ac9c96cf779b60119c - - -] Exception while checking dhcp_release6. Exception: Exit code: 127; Stdin: ; Stdout: ; Stderr: env: dhcp_release6: No such file or directory
 dhcp_release6_supported /usr/lib/python2.7/site-packages/neutron/cmd/sanity/checks.py:226
2018-02-12 08:28:58.314 97074 WARNING neutron.agent.linux.dhcp [req-ef61cc7b-5e3b-4e9d-b942-65246f63a126 9e16ad0a563d436e9f83533773c19e14 5f1b1e40249641ac9c96cf779b60119c - - -] dhcp_release6 is not present on this system, will not call it again.
2018-02-12 10:47:29.968 345841 DEBUG neutron.agent.linux.utils [req-a3a679b6-ba45-4ed0-b9f8-68302d338cd3 9e16ad0a563d436e9f83533773c19e14 5f1b1e40249641ac9c96cf779b60119c - - -] Running command: ['env', 'LC_ALL=C', 'dhcp_release6', '--help'] create_process /usr/lib/python2.7/site-packages/neutron/agent/linux/utils.py:89
2018-02-12 10:47:29.975 345841 ERROR neutron.agent.linux.utils [req-a3a679b6-ba45-4ed0-b9f8-68302d338cd3 9e16ad0a563d436e9f83533773c19e14 5f1b1e40249641ac9c96cf779b60119c - - -] Exit code: 127; Stdin: ; Stdout: ; Stderr: env: dhcp_release6: No such file or directory
2018-02-12 10:47:29.976 345841 DEBUG neutron.cmd.sanity.checks [req-a3a679b6-ba45-4ed0-b9f8-68302d338cd3 9e16ad0a563d436e9f83533773c19e14 5f1b1e40249641ac9c96cf779b60119c - - -] Exception while checking dhcp_release6. Exception: Exit code: 127; Stdin: ; Stdout: ; Stderr: env: dhcp_release6: No such file or directory
 dhcp_release6_supported /usr/lib/python2.7/site-packages/neutron/cmd/sanity/checks.py:226
2018-02-12 10:47:29.976 345841 WARNING neutron.agent.linux.dhcp [req-a3a679b6-ba45-4ed0-b9f8-68302d338cd3 9e16ad0a563d436e9f83533773c19e14 5f1b1e40249641ac9c96cf779b60119c - - -] dhcp_release6 is not present on this system, will not call it again.

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