mtpti5iD/redhat-docs_dataset huggingface dataset:
24.4.2. Using the blkid Command The blkid command allows you to display information about available block devices. To do so, type the following at a shell prompt as root : blkid For each listed block device, the blkid command displays available attributes such as its universally unique identifier ( UUID ), file system type ( TYPE ), or volume label ( LABEL ). For example: By default, the blkid command lists all available block devices. To display information about a particular device only, specify the device name on the command line: blkid device_name For instance, to display information about /dev/vda1 , type: You can also use the above command with the -p and -o udev command-line options to obtain more detailed information. Note that root privileges are required to run this command: blkid -po udev device_name For example: For a complete list of available command-line options, see the blkid (8) manual page.

Commands:
~]# blkid /dev/vda1: UUID="7fa9c421-0054-4555-b0ca-b470a97a3d84" TYPE="ext4" /dev/vda2: UUID="7IvYzk-TnnK-oPjf-ipdD-cofz-DXaJ-gPdgBW" TYPE="LVM2_member" /dev/mapper/vg_kvm-lv_root: UUID="a07b967c-71a0-4925-ab02-aebcad2ae824" TYPE="ext4" /dev/mapper/vg_kvm-lv_swap: UUID="d7ef54ca-9c41-4de4-ac1b-4193b0c1ddb6" TYPE="swap"
~]# blkid /dev/vda1 /dev/vda1: UUID="7fa9c421-0054-4555-b0ca-b470a97a3d84" TYPE="ext4"
~]# blkid -po udev /dev/vda1 ID_FS_UUID=7fa9c421-0054-4555-b0ca-b470a97a3d84 ID_FS_UUID_ENC=7fa9c421-0054-4555-b0ca-b470a97a3d84 ID_FS_VERSION=1.0 ID_FS_TYPE=ext4 ID_FS_USAGE=filesystem
Chapter 3. Post-deployment IPv6 operations After you deploy the overcloud with IPv6 networking, you must perform some additional configuration. Prerequisites A successful undercloud installation. For more information, see Installing director . A successful overcloud deployment. For more information, see Creating a basic overcloud with CLI tools . 3.1. Creating an IPv6 project network on the overcloud The overcloud requires an IPv6-based Project network for instances. Source the overcloudrc file and create an initial Project network in neutron . Prerequisites A successful undercloud installation. For more information, see Installing director . A successful overcloud deployment. For more information, see Creating a basic overcloud with CLI tools . Your network supports IPv6-native VLANs as well as IPv4-native VLANs. Procedure Source the overcloud credentials file: Create a network and subnet: This creates a basic neutron network called default . Verification steps Verify that the network was created successfully: 3.2. Creating an IPv6 public network on the overcloud After you configure the node interfaces to use the External network, you must create this network on the overcloud to enable network access. Prerequisites A successful undercloud installation. For more information, see Installing director . A successful overcloud deployment. For more information, see Creating a basic overcloud with CLI tools . Your network supports IPv6-native VLANs as well as IPv4-native VLANs. Procedure Create an external network and subnet: This command creates a network called public that provides an allocation pool of over 65000 IPv6 addresses for our instances. Create a router to route instance traffic to the External network.

Commands:
source ~/overcloudrc
openstack network create default --external --provider-physical-network datacentre --provider-network-type vlan --provider-segment 101 openstack subnet create default --subnet-range 2001:db8:fd00:6000::/64 --ipv6-address-mode slaac --ipv6-ra-mode slaac --ip-version 6 --network default
openstack network list openstack subnet list
openstack network create public --external --provider-physical-network datacentre --provider-network-type vlan --provider-segment 100 openstack subnet create public --network public --subnet-range 2001:db8:0:2::/64 --ip-version 6 --gateway 2001:db8::1 --allocation-pool start=2001:db8:0:2::2,end=2001:db8:0:2::ffff --ipv6-address-mode slaac --ipv6-ra-mode slaac
openstack router create public-router openstack router set public-router --external-gateway public
2. More to Come The Red Hat Enterprise Linux Introduction to System Adminitration is part of Red Hat, Inc's growing commitment to provide useful and timely support to Red Hat Enterprise Linux users. As new releases of Red Hat Enterprise Linux are made available, we make every effort to include both new and improved documentation for you. 2.1. Send in Your Feedback If you spot a typo in the Red Hat Enterprise Linux Introduction to System Adminitration , or if you have thought of a way to make this manual better, we would love to hear from you. Please submit a report in Bugzilla ( http://bugzilla.redhat.com/bugzilla ) against the component rhel-isa . If you mention this manual's identifier, we will know exactly which version of the guide you have. If you have a suggestion for improving the documentation, try to be as specific as possible. If you have found an error, please include the section number and some of the surrounding text so we can find it easily.

Commands:
30.3. Starting the tftp Server On the DHCP server, verify that the tftp-server package is installed with the command rpm -q tftp-server . tftp is an xinetd-based service; start it with the following commands: These commands configure the tftp and xinetd services to start at boot time in runlevels 3, 4, and 5.

Commands:
/sbin/chkconfig --level 345 xinetd on /sbin/chkconfig --level 345 tftp on
Chapter 5. Preparing a system with UEFI Secure Boot enabled to install and boot RHEL beta releases To enhance the security of your operating system, use the UEFI Secure Boot feature for signature verification when booting a Red Hat Enterprise Linux Beta release on systems having UEFI Secure Boot enabled. 5.1. UEFI Secure Boot and RHEL Beta releases UEFI Secure Boot requires that the operating system kernel is signed with a recognized private key. UEFI Secure Boot then verifies the signature using the corresponding public key. For Red Hat Enterprise Linux Beta releases, the kernel is signed with a Red Hat Beta-specific private key. UEFI Secure Boot attempts to verify the signature using the corresponding public key, but because the hardware does not recognize the Beta private key, Red Hat Enterprise Linux Beta release system fails to boot. Therefore, to use UEFI Secure Boot with a Beta release, add the Red Hat Beta public key to your system using the Machine Owner Key (MOK) facility. 5.2. Adding a Beta public key for UEFI Secure Boot This section contains information about how to add a Red Hat Enterprise Linux Beta public key for UEFI Secure Boot. Prerequisites The UEFI Secure Boot is disabled on the system. The Red Hat Enterprise Linux Beta release is installed, and Secure Boot is disabled even after system reboot. You are logged in to the system, and the tasks in the Initial Setup window are complete. Procedure Begin to enroll the Red Hat Beta public key in the system's Machine Owner Key (MOK) list: USD(uname -r) is replaced by the kernel version - for example, 4.18.0-80.el8.x86_64 . Enter a password when prompted. Reboot the system and press any key to continue the startup. The Shim UEFI key management utility starts during the system startup. Select Enroll MOK . Select Continue . Select Yes and enter the password. The key is imported into the system's firmware. Select Reboot . Enable Secure Boot on the system. 5.3. Removing a Beta public key If you plan to remove the Red Hat Enterprise Linux Beta release, and install a Red Hat Enterprise Linux General Availability (GA) release, or a different operating system, then remove the Beta public key. The procedure describes how to remove a Beta public key. Procedure Begin to remove the Red Hat Beta public key from the system's Machine Owner Key (MOK) list: Enter a password when prompted. Reboot the system and press any key to continue the startup. The Shim UEFI key management utility starts during the system startup. Select Reset MOK . Select Continue . Select Yes and enter the password that you had specified in step 2. The key is removed from the system's firmware. Select Reboot .

Commands:
mokutil --import /usr/share/doc/kernel-keys/USD(uname -r)/kernel-signing-ca.cer
mokutil --reset
Chapter 3. Distribution selection Red Hat provides several distributions of Red Hat build of OpenJDK. This module helps you select the distribution that is right for your needs. All distributions of OpenJDK contain the JDK Flight Recorder (JFR) feature. This feature produces diagnostics and profiling data that can be consumed by other applications, such as JDK Mission Control (JMC). Red Hat build of OpenJDK RPMs for RHEL 8 RPM distributions of Red Hat build of OpenJDK 8, Red Hat build of OpenJDK 11, and Red Hat build of OpenJDK 8 for RHEL 8. RHEL Portable Red Hat build of OpenJDK 8 JRE archive distribution for RHEL 7 and 8 hosts. Red Hat build of OpenJDK 8 portable archive for RHEL Portable Red Hat build of OpenJDK 8 archive distribution for RHEL 7 and 8 hosts. Red Hat build of OpenJDK 11 JRE portable archive for RHEL Portable Red Hat build of OpenJDK 11 JRE archive distribution for RHEL 7 and 8 hosts. Red Hat build of OpenJDK 11 portable archive for RHEL Portable Red Hat build of OpenJDK 11 archive distribution for RHEL 7 and 8 hosts. Red Hat build of OpenJDK 8 JRE portable archive for RHEL Portable Red Hat build of OpenJDK 8 JRE archive distribution for RHEL 7 and 8 hosts. Red Hat build of OpenJDK 8 portable archive for RHEL Portable Red Hat build of OpenJDK 8 archive distribution for RHEL 7 and 8 hosts. Red Hat build of OpenJDK archive for Windows Red Hat build of OpenJDK 8, Red Hat build of OpenJDK 11, and Red Hat build of OpenJDK 8 distributions for all supported Windows hosts. Recommended for cases where multiple Red Hat build of OpenJDK versions may be installed on a host. This distribution includes the following: Java Web Start Mission Control Red Hat build of OpenJDK installers for Windows Red Hat build of OpenJDK 8, Red Hat build of OpenJDK 11, and Red Hat build of OpenJDK 8 MSI installers for all supported Windows hosts. Optionally installs Java Web Start and sets environment variables. Suitable for system wide installs of a single Red Hat build of OpenJDK version. Additional resources For more information about the JDK Flight Recorder (JFR), see Introduction to JDK Flight Recorder . For more information about the JDK Flight Recorder (JFR), see Introduction to JDK Mission Control . JDK Mission Control is available for RHEL with Red Hat Software Collections 3.2 .

Commands:
2.2.11. Reverse Path Forwarding Reverse Path Forwarding is used to prevent packets that arrived via one interface from leaving via a different interface. When outgoing routes and incoming routes are different, it is sometimes referred to as asymmetric routing . Routers often route packets this way, but most hosts should not need to do this. Exceptions are such applications that involve sending traffic out over one link and receiving traffic over another link from a different service provider. For example, using leased lines in combination with xDSL or satellite links with 3G modems. If such a scenario is applicable to you, then turning off reverse path forwarding on the incoming interface is necessary. In short, unless you know that it is required, it is best enabled as it prevents users spoofing IP addresses from local subnets and reduces the opportunity for DDoS attacks. Note Red Hat Enterprise Linux 6 (unlike Red Hat Enterprise Linux 5) defaults to using Strict Reverse Path Forwarding . Red Hat Enterprise Linux 6 follows the Strict Reverse Path recommendation from RFC 3704, Ingress Filtering for Multihomed Networks. This currently only applies to IPv4 in Red Hat Enterprise Linux 6. Warning If forwarding is enabled, then Reverse Path Forwarding should only be disabled if there are other means for source-address validation (such as iptables rules for example). rp_filter Reverse Path Forwarding is enabled by means of the rp_filter directive. The rp_filter option is used to direct the kernel to select from one of three modes. It takes the following form when setting the default behavior: where INTEGER is one of the following: 0 - No source validation. 1 - Strict mode as defined in RFC 3704. 2 - Loose mode as defined in RFC 3704. The setting can be overridden per network interface using net.ipv4. interface .rp_filter . To make these settings persistent across reboot, modify the /etc/sysctl.conf file. 2.2.11.1. Additional Resources The following are resources that explain more about Reverse Path Forwarding. Installed Documentation usr/share/doc/kernel-doc- version /Documentation/networking/ip-sysctl.txt - This file contains a complete list of files and options available in the /proc/sys/net/ipv4/ directory. Useful Websites https://access.redhat.com/knowledge/solutions/53031 - The Red Hat Knowledgebase article about rp_filter . See RFC 3704 for an explanation of Ingress Filtering for Multihomed Networks.

Commands:
~]# /sbin/sysctl -w net.ipv4.conf.default.rp_filter= INTEGER
7.182. rhn-client-tools 7.182.1. RHBA-2015:1395 - rhn-client-tools bug fix update Updated rhn-client-tools packages that fix several bugs are now available for Red Hat Enterprise Linux 6. Red Hat Network Client Tools provide programs and libraries that allow a system to receive software updates from Red Hat Network. Bug Fixes BZ# 871028 When the rhnpush command was executed with the --server option, and the sslCACert variable was pointing to a non-existent path, rhnpush failed even when the connection to the server used the http protocol instead of https. With this update, rhnpush searches for CA certificate only when it is necessary, which prevents the described failure from occurring. BZ# 1003790 Previously, the rhn_check command returned an exception when processing a script that contained non-ascii characters. With this update, rhn_check accepts non-ascii characters as expected. BZ# 1036586 When executing the rhnpush command without any options, the command redundantly prompted for user credentials, and afterwards displayed a usage message about missing options. With this update, the command displays available options without asking for credentials. BZ# 1094776 Red Hat Network Client Tools did not calculate the CPU socket information on certain systems properly. With this update, rhn-client-tools parse the /proc/cpuinfo file correctly and thus provide the correct CPU socket information for all systems. BZ# 1147319 , BZ# 1147322 , BZ# 1147890 , BZ# 1147904 , BZ# 1147916 Several minor bugs have been fixed in various localizations of the Red Hat Network Client Tools GUI. BZ# 1147425 Previously, when running the "firstboot --reconfig" command on the system that was already registered with the Red Hat Subscription Management, the boot procedure failed on the Choose Service page. This bug has been fixed, and the exception no longer occurs on registered systems. Users of rhn-client-tools are advised to upgrade to these updated packages, which fix these bugs.

Commands:
6.4.3. Related Books The following books discuss various issues related to account and resource management, and are good resources for Red Hat Enterprise Linux system administrators. The Security Guide ; Red Hat, Inc - Provides an overview of the security-related aspects of user accounts, namely choosing strong passwords. The Reference Guide ; Red Hat, Inc - Contains detailed information on the users and groups present in Red Hat Enterprise Linux. The System Administrators Guide ; Red Hat, Inc - Includes a chapter on user and group configuration. Linux Administration Handbook by Evi Nemeth, Garth Snyder, and Trent R. Hein; Prentice Hall - Provides a chapter on user account maintenance, a section on security as it relates to user account files, and a section on file attributes and permissions.

Commands:
5.3. Performing Minimal PCP Setup to Gather File System Data The following procedure provides instructions on how to install a minimal PCP setup to collect statistics on Red Hat Enterprise Linux. The minimal setup involves adding the minimum number of packages on a production system needed to gather data for further analysis. The resulting tar.gz archive of the pmlogger output can be analyzed by using various PCP tools, such as PCP Charts, and compared with other sources of performance information. Install the pcp package: Start the pmcd service: Run the pmlogconf utility to update the pmlogger configuration and enable the XFS information, XFS data, and log I/O traffic groups: Start the pmlogger service: Perform operations on the XFS file system. Stop the pmlogger service: Collect the output and save it to a tar.gz file named based on the hostname and the current date and time:

Commands:
yum install pcp
systemctl start pmcd.service
pmlogconf -r /var/lib/pcp/config/pmlogger/config.default
systemctl start pmlogger.service
systemctl stop pmcd.service
systemctl stop pmlogger.service
cd /var/log/pcp/pmlogger/
tar -czf USD(hostname).USD(date +%F-%Hh%M).pcp.tar.gz USD(hostname)
Appendix A. General configuration options These are the general configuration options for Ceph. Note Typically, these will be set automatically by deployment tools, such as Ansible. fsid Description The file system ID. One per cluster. Type UUID Required No. Default N/A. Usually generated by deployment tools. admin_socket Description The socket for executing administrative commands on a daemon, irrespective of whether Ceph monitors have established a quorum. Type String Required No Default /var/run/ceph/USDcluster-USDname.asok pid_file Description The file in which the monitor or OSD will write its PID. For instance, /var/run/USDcluster/USDtype.USDid.pid will create /var/run/ceph/mon.a.pid for the mon with id a running in the ceph cluster. The pid file is removed when the daemon stops gracefully. If the process is not daemonized (meaning it runs with the -f or -d option), the pid file is not created. Type String Required No Default No chdir Description The directory Ceph daemons change to once they are up and running. Default / directory recommended. Type String Required No Default / max_open_files Description If set, when the Red Hat Ceph Storage cluster starts, Ceph sets the max_open_fds at the OS level (that is, the max # of file descriptors). It helps prevents Ceph OSDs from running out of file descriptors. Type 64-bit Integer Required No Default 0 fatal_signal_handlers Description If set, we will install signal handlers for SEGV, ABRT, BUS, ILL, FPE, XCPU, XFSZ, SYS signals to generate a useful log message. Type Boolean Default true

Commands:
9.9. Active Directory Authentication Using Kerberos (GSSAPI) When using Red Hat JBoss Data Grid with Microsoft Active Directory, data security can be enabled via Kerberos authentication. To configure Kerberos authentication for Microsoft Active Directory, use the following procedure. Procedure 9.6. Configure Kerberos Authentication for Active Directory (Library Mode) Configure JBoss EAP server to authenticate itself to Kerberos. This can be done by configuring a dedicated security domain, for example: The security domain for authentication must be configured correctly for JBoss EAP, an application must have a valid Kerberos ticket. To initiate the Kerberos ticket, you must reference another security domain using . This points to the standard Kerberos login module described in Step 3. The security domain authentication configuration described in the step points to the following standard Kerberos login module: Report a bug

Commands:
<security-domain name="ldap-service" cache-type="default"> <authentication> <login-module code="Kerberos" flag="required"> <module-option name="storeKey" value="true"/> <module-option name="useKeyTab" value="true"/> <module-option name="refreshKrb5Config" value="true"/> <module-option name="principal" value="ldap/localhost@INFINISPAN.ORG"/> <module-option name="keyTab" value="USD{basedir}/keytab/ldap.keytab"/> <module-option name="doNotPrompt" value="true"/> </login-module> </authentication> </security-domain>
<module-option name="usernamePasswordDomain" value="krb-admin"/>
<security-domain name="ispn-admin" cache-type="default"> <authentication> <login-module code="SPNEGO" flag="requisite"> <module-option name="password-stacking" value="useFirstPass"/> <module-option name="serverSecurityDomain" value="ldap-service"/> <module-option name="usernamePasswordDomain" value="krb-admin"/> </login-module> <login-module code="AdvancedAdLdap" flag="required"> <module-option name="password-stacking" value="useFirstPass"/> <module-option name="bindAuthentication" value="GSSAPI"/> <module-option name="jaasSecurityDomain" value="ldap-service"/> <module-option name="java.naming.provider.url" value="ldap://localhost:389"/> <module-option name="baseCtxDN" value="ou=People,dc=infinispan,dc=org"/> <module-option name="baseFilter" value="(krb5PrincipalName={0})"/> <module-option name="rolesCtxDN" value="ou=Roles,dc=infinispan,dc=org"/> <module-option name="roleFilter" value="(member={1})"/> <module-option name="roleAttributeID" value="cn"/> </login-module> </authentication> </security-domain>
<security-domain name="krb-admin" cache-type="default"> <authentication> <login-module code="Kerberos" flag="required"> <module-option name="useKeyTab" value="true"/> <module-option name="principal" value="admin@INFINISPAN.ORG"/> <module-option name="keyTab" value="USD{basedir}/keytab/admin.keytab"/> </login-module> </authentication> </security-domain>
Appendix A. Revision History Revision History Revision 0.3-06 Fri Aug 9 2019 Mirek Jahoda Version for 7.7 GA publication. Revision 0.3-05 Sat Oct 20 2018 Mirek Jahoda Version for 7.6 GA publication. Revision 0.3-03 Tue Apr 3 2018 Mirek Jahoda Version for 7.5 GA publication. Revision 0.3-01 Thu Jul 13 2017 Mirek Jahoda Version for 7.4 GA publication. Revision 0.2-18 Wed Nov 2 2016 Mirek Jahoda Version for 7.3 GA publication. Revision 0.2-11 Sun Jun 26 2016 Mirek Jahoda Async release with fixes. Revision 0.2-10 Sun Feb 14 2016 Robert Kratky Async release with fixes. Revision 0.2-9 Thu Dec 10 2015 Barbora Ancincova Added the Red Hat Gluster Storage chapter. Revision 0.2-8 Thu Nov 11 2015 Barbora Ancincova Red Hat Enterprise Linux 7.2 GA release of the book. Revision 0.2-7 Thu Aug 13 2015 Barbora Ancincova Red Hat Enterprise Linux 7.2 Beta release of the book. Revision 0.2-6 Wed Feb 18 2015 Barbora Ancincova Red Hat Enterprise Linux 7.1 GA release of the book. Revision 0.2-5 Fri Dec 05 2014 Barbora Ancincova Update to sort order on the Red Hat Customer Portal. Revision 0.2-4 Thu Dec 04 2014 Barbora Ancincova Red Hat Enterprise Linux 7.1 Beta release of the book. Revision 0.1-41 Tue May 20 2014 Tomas Capek Rebuild for style changes. Revision 0.1-1 Tue Jan 17 2013 Tomas Capek Initial creation of the book for Red Hat Enterprise Linux 7

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