mtpti5iD/redhat-docs_dataset huggingface dataset:
B.9. Glock Statistics GFS2 maintains statistics that can help track what is going on within the file system. This allows you to spot performance issues. GFS2 maintains two counters: dcount , which counts the number of DLM operations requested. This shows how much data has gone into the mean/variance calculations. qcount , which counts the number of syscall level operations requested. Generally qcount will be equal to or greater than dcount . In addition, GFS2 maintains three mean/variance pairs. The mean/variance pairs are smoothed exponential estimates and the algorithm used is the one used to calculate round trip times in network code. The mean and variance pairs maintained in GFS2 are not scaled, but are in units of integer nanoseconds. srtt/srttvar: Smoothed round trip time for non-blocking operations srttb/srttvarb: Smoothed round trip time for blocking operations irtt/irttvar: Inter-request time (for example, time between DLM requests) A non-blocking request is one which will complete right away, whatever the state of the DLM lock in question. That currently means any requests when (a) the current state of the lock is exclusive (b) the requested state is either null or unlocked or (c) the "try lock" flag is set. A blocking request covers all the other lock requests. Larger times are better for IRTTs, whereas smaller times are better for the RTTs. Statistics are kept in two sysfs files: The glstats file. This file is similar to the glocks file, except that it contains statistics, with one glock per line. The data is initialized from "per cpu" data for that glock type for which the glock is created (aside from counters, which are zeroed). This file may be very large. The lkstats file. This contains "per cpu" stats for each glock type. It contains one statistic per line, in which each column is a cpu core. There are eight lines per glock type, with types following on from each other.

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1.2. Why Virtualization Security Matters Deploying virtualization in your infrastructure provides many benefits, but can also introduce new risks. Virtualized resources and services should be deployed with the following security considerations: The host and hypervisor become prime targets; they are often a single point of failure for guests and data. Virtual machines can interfere with each other in undesirable ways. If no access controls are in place to help prevent this, one malicious guest can bypass a vulnerable hypervisor and directly access other resources on the host system, such as the storage of other guests. Resources and services can become difficult to track and maintain; with rapid deployment of virtualized systems comes an increased need for management of resources, including sufficient patching, monitoring and maintenance. Resources such as storage can be spread across, and dependent upon, several machines. This can lead to overly complex environments and poorly managed and maintained systems. Virtualization does not remove any of the traditional security risks present in your environment; the entire solution stack, not just the virtualization layer, must be secured. This guide aims to assist you in mitigating your security risks by offering a number of virtualization recommended practices for Red Hat Enterprise Linux that will help you secure your virtualized infrastructure.

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3.5.2. How This Affects Load Balancer Add-On Routing IPVS packet forwarding only allows connections in and out of the cluster based on it recognizing its port number or its firewall mark. If a client from outside the cluster attempts to open a port IPVS is not configured to handle, it drops the connection. Similarly, if the real server attempts to open a connection back out to the Internet on a port IPVS does not know about, it drops the connection. This means all connections from FTP clients on the Internet must have the same firewall mark assigned to them and all connections from the FTP server must be properly forwarded to the Internet using network packet filtering rules. Note In order to enable passive FTP connections, ensure that you have the ip_vs_ftp kernel module loaded, which you can do by running the command modprobe ip_vs_ftp as an administrative user at a shell prompt.

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Chapter 1. New features and enhancements Red Hat JBoss Core Services (JBCS) 2.4.57 Service Pack 3 includes the following new features and enhancements. 1.1. ResponseStatusCodeOnNoContext directive for mod_proxy_cluster From the JBCS 2.4.57 Service Pack 3 release onward, the mod_proxy_cluster module also includes a ResponseStatusCodeOnNoContext directive. You can use the ResponseStatusCodeOnNoContext directive to specify the response status code that the server sends to the client when a ProxyPass or ProxyPassMatch directive does not have a matching context. The default status code is 404 . Note In JBCS 2.4.51 or earlier, when a ProxyPass or ProxyPassMatch directive did not have a matching context, the server sent a 503 status code by default. If you want to preserve the default behavior that was available in earlier releases, set the ResponseStatusCodeOnNoContext directive to 503 instead. If you specify a value other than a standard HTTP response code, the server access log shows the specified value but the server sends a 500 Internal Server Error response to the client.

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25.8. Debugging Rsyslog To run rsyslogd in debugging mode, use the following command: rsyslogd -dn With this command, rsyslogd produces debugging information and prints it to the standard output. The -n stands for "no fork". You can modify debugging with environmental variables, for example, you can store the debug output in a log file. Before starting rsyslogd , type the following on the command line: Replace path with a desired location for the file where the debugging information will be logged. For a complete list of options available for the RSYSLOG_DEBUG variable, see the related section in the rsyslogd(8) manual page. To check if syntax used in the /etc/rsyslog.conf file is valid use: rsyslogd -N 1 Where 1 represents level of verbosity of the output message. This is a forward compatibility option because currently, only one level is provided. However, you must add this argument to run the validation.

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export RSYSLOG_DEBUGLOG=" path " export RSYSLOG_DEBUG="Debug"
4.249. python-rhsm 4.249.1. RHBA-2011:1696 - python-rhsm bug fix update An updated python-rhsm package that fixes multiple bugs is now available for Red Hat Enterprise Linux 6. The python-rhsm package contains a small library for communicating with the representational state transfer (REST) interface of a Red Hat Unified Entitlement Platform. This interface is used for the management of system entitlements, certificates, and access to content. Bug Fixes BZ# 700601 Prior to this update, the firstboot utility was trying to set an erroneous environment variable LANG=us. As a result, firstboot was unable to start properly. With this update, the C locale is now used as the fallback locale so that the problem does not occur anymore. BZ# 719378 If a user name containing a white space was submitted during the registration process in the Subscription Manager, an incorrect error message was displayed. This problem has been fixed in this update so that the correct error message "Invalid credentials" is now displayed. BZ# 728266 If a subscription was selected in the My Subscriptions tab in the Subscription Manager, and then the Unsubscribe button was pressed, an error occurred. With this update, the problem has been fixed so that the unsubscribe function in the Subscription Manager now works, as expected. BZ# 736166 The /etc/rhsm/ca/candlepin-stage.pem, /etc/rhsm/ca/fakamai-cp1.pem, and /etc/rhsm/ca/redhat-uep.pem certificates have been moved to the updated python-rhsm package so that it is now possible for python-rhsm to register with the hosted Candlepin system. BZ# 746241 If the rhsmcertd daemon received information about an existing update, but no products were installed, an exception occurred. Also, if the virt-who agent attempted to update the guest systems of a host, but there were no guest systems available, an exception occurred. All users of python-rhsm are advised to upgrade to this updated package, which fixes these bugs.

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Chapter 3. Predefined User Access roles The following table lists the predefined roles provided with User Access. Some of the predefined roles are included in the Default access group, which includes all authenticated users in your organization. Only the Organization Administrator users in your organization inherit the roles in the Default admin access group. Because this group is provided by Red Hat, it is updated automatically when Red Hat assigns roles to the Default admin access group. For more information about viewing predefined roles, see Chapter 2, Procedures for configuring User Access . NOTE Predefined roles are updated and modified by Red Hat and cannot be modified. The table might not contain all currently available predefined roles. Table 3.1. Predefined roles provided with User Access Role name Description Default access group Default admin access group Compliance administrator A Compliance role that grants full access to any Compliance resource. X Compliance viewer A Compliance role that grants read access to any Compliance resource. X RHEL Advisor administrator Perform any available operation against any RHEL Advisor resource. X Inventory Groups Administrator Be able to read and edit Inventory Groups data. X Inventory Groups Viewer Be able to read Inventory Groups data. Inventory Hosts Administrator Be able to read and edit Inventory Hosts data. X X Inventory Hosts Viewer Be able to read Inventory Hosts data. Inventory administrator Perform any available operation against any Inventory resource. Malware detection administrator Perform any available operation against any malware-detection resource. X Malware detection viewer Read any malware-detection resource. Notifications administrator Perform any available operation against Notifications and Integrations applications. X Notifications viewer Read only access to notifications and integrations applications. Patch administrator Perform any available operation against any Patch resource. X Patch viewer Read any Patch resource. X Policies administrator Perform any available operation against any Policies resource. X Policies viewer Perform read only operation against any Policies resource. X Remediations administrator Perform any available operation against any Remediations resource Remediations user Perform create, view, update, delete operations against any Remediations resource. X Resource Optimization administrator Perform any available operation against any Resource Optimization resource. X Resource Optimization user A Resource Optimization user role that grants read only permission. X Tasks administrator Perform any available operation against any Tasks resource. X User Access administrator Grants a non-org admin full access to configure and manage user access to services hosted on console.redhat.com. This role can only be viewed and assigned by Organization Administrators. User Access principal viewer Grants a non-org admin read access to principals within user access. Vulnerability administrator Perform any available operation against any Vulnerability resource. X Vulnerability viewer Read any Vulnerability resource. X

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8.63. hdparm 8.63.1. RHBA-2013:1580 - hdparm bug fix and enhancement update Updated hdparm packages that fix several bugs and add various enhancements are now available for Red Hat Enterprise Linux 6. Hdparm is a useful system utility for setting (E)IDE hard drive parameters. For example, hdparm can be used to tweak hard drive performance and to spin down hard drives for power conservation. Note The hdparm packages have been upgraded to upstream version 9.43, which provides a number of bug fixes and enhancements over the version. These enhancements include creating files with the desired size on the ext4 and xfs filesystems, and a possibility to specify the offset for reading operations when measuring timing performance. Other notable enhancements include an ability to obtain and set the "idle3" timeout value of the Western Digital Green (WDG) hard drive, and an ability to obtain and set the Write-Read-Verify feature for hard drives. (BZ# 977800 ) Bug Fixes BZ# 639623 Previously, the hdparm utility did not assume that some disk information could be unavailable. As a consequence, hdparm could terminate unexpectedly with no useful output. With this update, proper checks for unsuccessful disk queries have been added, and hdparm now terminates with a more detailed error message. BZ# 735887 Prior to this update, the hdparm utility did not assume that some disk information could be unavailable when the user requested information about how much disk space a file occupied. Consequently, hdparm terminated unexpectedly with no useful output in such a scenario. With this update, proper checks for unsuccessful disk queries have been added. As a result, hdparm now terminates with an error message providing detailed information. BZ# 807056 Previously, the hdparm utility retrieved the hard drive identification data in a way that could cause errors. As a consequence, hdparm failed to obtain the data on some occasions and displayed an unhelpful error message. With this update, the respective system call has been replaced with one that is more appropriate and robust. As a result, the hard drive identification data is now successfully obtained and printed in the output. BZ# 862257 When the hdparm utility is unable to obtain the necessary geometry information about a hard drive, it attempts to download firmware. Previously, due to incorrect control statements, hdparm could terminate unexpectedly with a segmentation fault at such a download attempt. With this update, control statements checking for system call failures have been added. As a result, if hdparm cannot operate on a drive, it displays an error message and exits cleanly. Users of hdparm are advised to upgrade to these updated packages, which fix these bugs and add these enhancements.

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3.9. Virtual LAN (VLAN) A VLAN (Virtual LAN) is an attribute that can be applied to network packets. Network packets can be "tagged" into a numbered VLAN. A VLAN is a security feature used to completely isolate network traffic at the switch level. VLANs are completely separate and mutually exclusive. The Red Hat Virtualization Manager is VLAN aware and able to tag and redirect VLAN traffic, however VLAN implementation requires a switch that supports VLANs. At the switch level, ports are assigned a VLAN designation. A switch applies a VLAN tag to traffic originating from a particular port, marking the traffic as part of a VLAN, and ensures that responses carry the same VLAN tag. A VLAN can extend across multiple switches. VLAN tagged network traffic on a switch is completely undetectable except by machines connected to a port designated with the correct VLAN. A given port can be tagged into multiple VLANs, which allows traffic from multiple VLANs to be sent to a single port, to be deciphered using software on the machine that receives the traffic.

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Chapter 22. Internationalization 22.1. RHEL 8 International Languages Red Hat Enterprise Linux 8 supports the installation of multiple languages and the changing of languages based on your requirements. East Asian Languages - Japanese, Korean, Simplified Chinese, and Traditional Chinese. European Languages - English, German, Spanish, French, Italian, Portuguese, and Russian. The following table lists the fonts and input methods provided for various major languages. Language Default Font (Font Package) Input Methods English dejavu-sans-fonts French dejavu-sans-fonts German dejavu-sans-fonts Italian dejavu-sans-fonts Russian dejavu-sans-fonts Spanish dejavu-sans-fonts Portuguese dejavu-sans-fonts Simplified Chinese google-noto-sans-cjk-ttc-fonts, google-noto-serif-cjk-ttc-fonts ibus-libpinyin, libpinyin Traditional Chinese google-noto-sans-cjk-ttc-fonts, google-noto-serif-cjk-ttc-fonts ibus-libzhuyin, libzhuyin Japanese google-noto-sans-cjk-ttc-fonts, google-noto-serif-cjk-ttc-fonts ibus-kkc, libkkc Korean google-noto-sans-cjk-ttc-fonts, google-noto-serif-cjk-ttc-fonts ibus-hangul, libhangu 22.2. Notable changes to internationalization in RHEL 8 RHEL 8 introduces the following changes to internationalization compared to RHEL 7: Support for the Unicode 11 computing industry standard has been added. Internationalization is distributed in multiple packages, which allows for smaller footprint installations. For more information, see Using langpacks . The glibc package updates for multiple locales are now synchronized with the Common Locale Data Repository (CLDR).

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21.9. Enabling and Disabling Counters The nsslapd-counters parameter enabled counters to run. However, running counters can affect performance, so it also possible to turn off counters. If counters are off, they all have a value of zero (0). By default, counters are already enabled. To enable or disable performance counters, use ldapmodify . For example, to disable:

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dsconf -D "cn=Directory Manager" ldap://server.example.com config replace nsslapd-counters=off
Preface Self-hosted engine installation is automated using Ansible. The installation script ( hosted-engine --deploy ) runs on an initial deployment host, and the Red Hat Virtualization Manager (or "engine") is installed and configured on a virtual machine that is created on the deployment host. The Manager and Data Warehouse databases are installed on the Manager virtual machine, but can be migrated to a separate server post-installation if required. Hosts that can run the Manager virtual machine are referred to as self-hosted engine nodes. At least two self-hosted engine nodes are required to support the high availability feature. A storage domain dedicated to the Manager virtual machine is referred to as the self-hosted engine storage domain. This storage domain is created by the installation script, so the underlying storage must be prepared before beginning the installation. See the Planning and Prerequisites Guide for information on environment options and recommended configuration. See Self-Hosted Engine Recommendations for configuration specific to a self-hosted engine environment. Red Hat Virtualization Key Components Component Name Description Red Hat Virtualization Manager A service that provides a graphical user interface and a REST API to manage the resources in the environment. The Manager is installed on a physical or virtual machine running Red Hat Enterprise Linux. Hosts Red Hat Enterprise Linux hosts (RHEL hosts) and Red Hat Virtualization Hosts (image-based hypervisors) are the two supported types of host. Hosts use Kernel-based Virtual Machine (KVM) technology and provide resources used to run virtual machines. Shared Storage A storage service is used to store the data associated with virtual machines. Data Warehouse A service that collects configuration information and statistical data from the Manager. Self-Hosted Engine Architecture The Red Hat Virtualization Manager runs as a virtual machine on self-hosted engine nodes (specialized hosts) in the same environment it manages. A self-hosted engine environment requires one less physical server, but requires more administrative overhead to deploy and manage. The Manager is highly available without external HA management. The minimum setup of a self-hosted engine environment includes: One Red Hat Virtualization Manager virtual machine that is hosted on the self-hosted engine nodes. The RHV-M Appliance is used to automate the installation of a Red Hat Enterprise Linux 8 virtual machine, and the Manager on that virtual machine. A minimum of two self-hosted engine nodes for virtual machine high availability. You can use Red Hat Enterprise Linux hosts or Red Hat Virtualization Hosts (RHVH). VDSM (the host agent) runs on all hosts to facilitate communication with the Red Hat Virtualization Manager. The HA services run on all self-hosted engine nodes to manage the high availability of the Manager virtual machine. One storage service, which can be hosted locally or on a remote server, depending on the storage type used. The storage service must be accessible to all hosts. Figure 1. Self-Hosted Engine Red Hat Virtualization Architecture

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Chapter 7. Clustering 7.1. Clustering in Red Hat JBoss Data Virtualization Clustering may be used to improve the performance of the system through: Load Balancing See Red Hat JBoss Data Virtualization Development Guide: Client Development for information on load balancing between multiple nodes. Failover See Red Hat JBoss Data Virtualization Development Guide: Client Development for information on failover with multiple nodes. Distributed Caching In cluster mode, resultsset caches and internal materialization caches are shared across the cluster automatically. Therefore no further configuration is needed. Event Distribution Metadata and data modifications will be distributed to all members of a cluster automatically when clustering is configured.

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2.2. Graphical Installer This section describes what behaviors have changed in the graphical installer. 2.2.1. Devices and Disks Use of the /dev/hd X device name is deprecated on the i386 and x86_64 architecture for IDE drives, and has changed to /dev/sd X . This change does not apply to the PPC architecture. If you have difficulties with the installation not detecting a Smart Array card, enter linux isa at the installer prompt. This lets you manually select the required card. Whereas older IDE drivers supported up to 63 partitions per device, SCSI devices are limited to 15 partitions per device. Anaconda uses the new libata driver in the same fashion as the rest of Red Hat Enterprise Linux, so it is unable to detect more than 15 partitions on an IDE disk during the installation or upgrade process. If you are upgrading a system with more than 15 partitions, migrating the disk to Logical Volume Manager (LVM) is recommended. A change in the way that the kernel handles storage devices means that device names like /dev/hd X or /dev/sd X can differ from the values used in earlier releases. Anaconda solves this problem by relying on partition labels. If these labels are not present, then Anaconda provides a warning that these partitions need to be labeled. Systems that use Logical Volume Management (LVM) and the device mapper usually do not require relabeling. With the inclusion of the Linux Unified Key Setup (LUKS) specification, support is included for installation to encrypted block devices, including the root file system. Refer to the Red Hat Enterprise Linux Installation Guide for more information on LUKS. Not all IDE RAID controllers are supported. If your RAID controller is not yet supported by dmraid , it is possible to combine drives into RAID arrays by configuring Linux software RAID. For supported controllers, configure the RAID functions in the computer BIOS. The version of GRUB included in Red Hat Enterprise Linux 6 now supports ext4, so Anaconda now allows you to use the ext4 file system on any partition, including the /boot and root partitions.

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