mtpti5iD/redhat-docs_dataset huggingface dataset:
Chapter 3. Tuning the Number of Locks Lock mechanisms in Directory Server control how many copies of Directory Server processes can run at the same time. For example, during an import job, Directory Server sets a lock in the /run/lock/dirsrv/slapd- instance_name /imports/ directory to prevent the ns-slapd (Directory Server) process, another import, or export operations from running. If the server runs out of available locks, the following error is logged in the /var/log/dirsrv/slapd- instance_name /errors file: If error messages indicate that the lock table is out of available locks, double the number of locks. If the problem persists, double the value again. 3.1. Manually Monitoring the Number of Locks To monitor the number of locks using the command line, enter: For details about the monitoring attributes, see the descriptions in the Directory Server Configuration, Command, and File Reference .

Commands:
libdb: Lock table is out of available locks
ldapsearch -D "cn=Directory Manager" -W -p 389 -h server.example.com -x -s sub -b "cn=database,cn=monitor,cn=ldbm database,cn=plugins,cn=config" nsslapd-db-current-locks nsslapd-db-max-locks
Chapter 2. Adding a single system to a group In the Insights Workspaces application, you can add a single system to a group to manage it more easily. For example, you can easily mitigate vulnerabilities and update systems that are alike. With the Insights inventory group application, you can add a system to only one group. Prerequisites You have a Red Hat Hybrid Cloud Console account. You have registered the systems you plan to group with the Insights Inventory application. Procedure Access Red Hat Hybrid Cloud Console platform and log in. From the console dashboard, navigate to Red Hat Insights > RHEL > Inventory > Systems . On the System page, add a single system to a group: Click the options icon (...) near the image and click Add to group . The Add to group window open: Select one of the options: Add to an existing group: Select an existing group and click Add . Create a new group: Click the Create group button. Click Add . Verification If adding systems to the group was successful, you can see the systems added to the group on the page for your group.

Commands:
3.2. Logical Volume Creation Overview The following is a summary of the steps to perform to create an LVM logical volume. Initialize the partitions you will use for the LVM volume as physical volumes (this labels them). Create a volume group. Create a logical volume. After creating the logical volume you can create and mount the file system. The examples in this document use GFS file systems. Create a GFS file system on the logical volume with the gfs_mkfs command. Create a new mount point with the mkdir command. In a clustered system, create the mount point on all nodes in the cluster. Mount the file system. You may want to add a line to the fstab file for each node in the system. Alternately, you can create and mount the GFS file system with the LVM GUI. Creating the LVM volume is machine independent, since the storage area for LVM setup information is on the physical volumes and not the machine where the volume was created. Servers that use the storage have local copies, but can recreate that from what is on the physical volumes. You can attach physical volumes to a different server if the LVM versions are compatible.

Commands:
Chapter 2. Running Java applications with Shenandoah garbage collector You can run your Java application with the Shenandoah garbage collector (GC). Prerequisites Installed Red Hat build of OpenJDK. See Installing Red Hat build of OpenJDK 11 on Red Hat Enterprise Linux in the Installing and using Red Hat build of OpenJDK 11 on RHEL guide. Procedure Run your Java application with Shenandoah GC by using the -XX:+UseShenandoahGC JVM option. USD java <PATH_TO_YOUR_APPLICATION> -XX:+UseShenandoahGC

Commands:
java <PATH_TO_YOUR_APPLICATION> -XX:+UseShenandoahGC
Appendix D. Ceph File System mirrors configuration reference This section lists configuration options for Ceph File System (CephFS) mirrors. cephfs_mirror_max_concurrent_directory_syncs Description Maximum number of directory snapshots that can be synchronized concurrently by cephfs-mirror daemon. Controls the number of synchronization threads. Type Integer Default 3 Min 1 cephfs_mirror_action_update_interval Description Interval in seconds to process pending mirror update actions. Type secs Default 2 Min 1 cephfs_mirror_restart_mirror_on_blocklist_interval Description Interval in seconds to restart blocklisted mirror instances. Setting to zero ( 0 ) disables restarting blocklisted instances. Type secs Default 30 Min 0 cephfs_mirror_max_snapshot_sync_per_cycle Description Maximum number of snapshots to mirror when a directory is picked up for mirroring by worker threads. Type Integer Default 3 Min 1 cephfs_mirror_directory_scan_interval Description Interval in seconds to scan configured directories for snapshot mirroring. Type Integer Default 10 Min 1 cephfs_mirror_max_consecutive_failures_per_directory Description Number of consecutive snapshot synchronization failures to mark a directory as "failed". Failed directories are retried for synchronization less frequently. Type Integer Default 10 Min 0 cephfs_mirror_retry_failed_directories_interval Description Interval in seconds to retry synchronization for failed directories. Type Integer Default 60 Min 1 cephfs_mirror_restart_mirror_on_failure_interval Description Interval in seconds to restart failed mirror instances. Setting to zero ( 0 ) disables restarting failed mirror instances. Type secs Default 20 Min 0 cephfs_mirror_mount_timeout Description Timeout in seconds for mounting primary or secondary CephFS by the cephfs-mirror daemon. Setting this to a higher value could result in the mirror daemon getting stalled when mounting a file system if the cluster is not reachable. This option is used to override the usual client_mount_timeout . Type secs Default 10 Min 0

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Chapter 3. Getting started This chapter guides you through the steps to set up your environment and run a simple messaging program. 3.1. Prerequisites You must complete the installation procedure for your environment. You must have an AMQP 1.0 message broker listening for connections on interface localhost and port 5672 . It must have anonymous access enabled. For more information, see Starting the broker . You must have a queue named examples . For more information, see Creating a queue . 3.2. Running Hello World on Red Hat Enterprise Linux The Hello World example creates a connection to the broker, sends a message containing a greeting to the examples queue, and receives it back. On success, it prints the received message to the console. Procedure Copy the examples to a location of your choosing. USD cp -r /usr/share/proton/examples/cpp cpp-examples Create a build directory and change to that directory: USD mkdir cpp-examples/bld USD cd cpp-examples/bld Use cmake to configure the build and use make to compile the examples. USD cmake .. USD make Run the helloworld program. USD ./helloworld Hello World!

Commands:
cp -r /usr/share/proton/examples/cpp cpp-examples
mkdir cpp-examples/bld cd cpp-examples/bld
cmake .. make
./helloworld Hello World!
Part III. Managing assets in Business Central As a process administrator, you can use Business Central in Red Hat Decision Manager to manage assets, such as rules, business processes, and decision tables. Prerequisites Red Hat JBoss Enterprise Application Platform 7.4 is installed. For details, see Red Hat JBoss Enterprise Application Platform 7.4 Installation Guide . Red Hat Process Automation Manager is installed and configured with KIE Server. For more information see Installing and configuring Red Hat Decision Manager on Red Hat JBoss EAP 7.4 . Red Hat Decision Manager is running and you can log in to Business Central with the developer role. For more information, see Planning a Red Hat Decision Manager installation .

Commands:
11.3.2. Postfix Originally developed at IBM by security expert and programmer Wietse Venema, Postfix is a Sendmail-compatible MTA that is designed to be secure, fast, and easy to configure. To improve security, Postfix uses a modular design, where small processes with limited privileges are launched by a master daemon. The smaller, less privileged processes perform very specific tasks related to the various stages of mail delivery and run in a change rooted environment to limit the effects of attacks. Configuring Postfix to accept network connections from hosts other than the local computer takes only a few minor changes in its configuration file. Yet for those with more complex needs, Postfix provides a variety of configuration options, as well as third party add ons that make it a very versatile and full-featured MTA. The configuration files for Postfix are human readable and support upward of 250 directives. Unlike Sendmail, no macro processing is required for changes to take effect and the majority of the most commonly used options are described in the heavily commented files. Important Before using Postfix, the default MTA must be switched from Sendmail to Postfix. Refer to the chapter called Mail Transport Agent (MTA) Configuration in the System Administrators Guide for further details. 11.3.2.1. The Default Postfix Installation The Postfix executable is /usr/sbin/postfix . This daemon launches all related processes needed to handle mail delivery. Postfix stores its configuration files in the /etc/postfix/ directory. The following is a list of the more commonly used files: access - Used for access control, this file specifies which hosts are allowed to connect to Postfix. aliases - A configurable list required by the mail protocol. main.cf - The global Postfix configuration file. The majority of configuration options are specified in this file. master.cf - Specifies how Postfix interacts with various processes to accomplish mail delivery. transport - Maps email addresses to relay hosts. Important The default /etc/postfix/main.cf file does not allow Postfix to accept network connections from a host other than the local computer. For instructions on configuring Postfix as a server for other clients, refer to Section 11.3.2.2, "Basic Postfix Configuration" . When changing some options within files in the /etc/postfix/ directory, it may be necessary to restart the postfix service for the changes to take effect. The easiest way to do this is to type the following command:

Commands:
service postfix restart
5.7. Managing Nodes with Fence Devices You can fence a node manually with the following command. If you specify --off this will use the off API call to stonith which will turn the node off instead of rebooting it. In a situation where no stonith device is able to fence a node even if it is no longer active, the cluster may not be able to recover the resources on the node. If this occurs, after manually ensuring that the node is powered down you can enter the following command to confirm to the cluster that the node is powered down and free its resources for recovery. Warning If the node you specify is not actually off, but running the cluster software or services normally controlled by the cluster, data corruption/cluster failure will occur.

Commands:
pcs stonith fence node [--off]
pcs stonith confirm node
Chapter 12. Networking NetworkManager-openswan now supports libreswan In Red Hat Enterprise Linux 6.8, the openswan IPsec implementation is considered obsolete and replaced by the libreswan implementation. The NetworkManager-openswan package now supports both openswan and libreswan in order to facilitate migration. (BZ#1267394) New package: chrony A new package, chrony , has been added to Red Hat Enterprise Linux 6. chrony is a versatile implementation of the Network Time Protocol (NTP), which can usually synchronize the system clock with a better accuracy than the ntpd daemon from the ntp package. It can be also used with the timemaster service from the linuxptp package to synchronize the clock to Precision Time Protocol (PTP) domains with sub-microsecond accuracy if hardware timestamping is available, and provide a fallback to other PTP domains or NTP sources. (BZ#1274811) New packages: ldns The ldns packages contain a library with the aim to simplify DNS programming in C. All low-level DNS/DNSSEC operations are supported. A higher level API has been defined which allows a programmer to, for instance, create or sign packets. (BZ#1284961) wpa_supplicant can now send logs into the syslog Previously, wpa_supplicant could only save log messages into the /var/log/wpa_supplicant.log file. This update adds the capability to save log messages into the system log, allowing you to use additional features provided by syslog such as remote logging. To activate this feature, add the new -s option into OTHER_ARGS in the /etc/sysconfig/wpa_supplicant configuration file. (BZ#822128) Enhancements in system-config-network The Network Configuration tool (the system-config-network package) has received multiple user interface improvements in this release. Notable enhancements include additional fields for the PEERDNS and ONBOOT settings and an added Delete button in the list of interfaces. (BZ#1214729) New packages: unbound Unbound is a validating, recursive, and caching DNS resolver. It is designed as a set of modular components that also support DNS Security Extensions (DNSSEC). (BZ#1284964) nm-connection-editor now allows a higher range of VLAN ids The VLAN id is no longer limited to the range 0-100 in nm-connection-editor . The new allowed range is between 0 and 4095. (BZ#1258218) NetworkManager supports locking Wi-Fi network connections to a specific radio frequency band NetworkManager now allows you to specify a certain frequency band such for a Wi-Fi connection. To lock a connection to a certain band, use the new BAND= option in the connection configuration file in the /etc/sysconfig/network-scripts/ directory. Values for this option are based on the IEEE 802.11 protocol specifications; to specify the 2.4 GHz band, use BAND=bg , and to specify the 5 GHz band, use BAND=a . (BZ#1254070) NetworkManager now supports iBFT A plug-in for iSCSI Boot Firmware Table (iBFT) configuration has been added to NetworkManager . This plug-in ensures that initial network configuration for hosts booting from iSCSI in a VLAN is correct. (BZ#1198325)

Commands:
Chapter 3. Role-Based Parameters You can modify the bevavior of specific overcloud composable roles with overcloud role-based parameters. Substitute _ROLE_ with the name of the role. For example, for _ROLE_Count use ControllerCount . Parameter Description _ROLE_AnyErrorsFatal Sets the any_errors_fatal value when running config-download Ansible playbooks. The default value is yes . _ROLE_ControlPlaneSubnet Name of the subnet on ctlplane network for this role. The default value is ctlplane-subnet . _ROLE_Count The number of nodes to deploy in a role. The default value is 1 . _ROLE_ExtraConfig Role specific additional hiera configuration to inject into the cluster. _ROLE_ExtraGroupVars Optional extra Ansible group vars. _ROLE_HostnameFormat Format for node hostnames. Note that %index% is translated into the index of the node (e.g 0/1/2) and %stackname% is replaced with the stack name (e.g overcloud ). The default value is %stackname%-_role_-%index% . _ROLE_LocalMtu MTU to use for the Undercloud local_interface. The default value is 1500 . _ROLE_MaxFailPercentage Sets the max_fail_percentage value when running config-download Ansible playbooks. The default value is 0 . _ROLE_NetConfigOverride Custom JSON data to be used to override the os-net-config config. This is meant to be used by net_config_override parameter in tripleoclient to provide an easy means to pass in custom net configs for the Undercloud. _ROLE_NetworkConfigTemplate ROLE NetworkConfig Template. _ROLE_NetworkConfigUpdate When set to "True", existing networks will be updated on the overcloud. This parameter replaces the functionality previously provided by NetworkDeploymentActions. Defaults to "False" so that only new nodes will have their networks configured. This is a role based parameter. The default value is False . _ROLE_Parameters Optional Role Specific parameters to be provided to service. _ROLE_RemovalPolicies List of resources to be removed from the role's ResourceGroup when doing an update that requires removal of specific resources. _ROLE_RemovalPoliciesMode How to handle change to RemovalPolicies for ROLE ResourceGroup when doing an update. Default mode append will append to the existing blocklist and update would replace the blocklist. The default value is append . _ROLE_SchedulerHints Optional scheduler hints to pass to OpenStack Compute (nova). _ROLE_ServiceNetMap Role specific ServiceNetMap overrides, the map provided will be merged with the global ServiceNetMap when passing the ServiceNetMap to the ROLE_ServiceChain resource and the _ROLE resource group. For example: _ROLE_ServiceNetMap: NovaLibvirtNetwork: internal_api_leaf2. _ROLE_Services A list of service resources (configured in the OpenStack Orchestration (heat) resource_registry) which represent nested stacks for each service that should get installed on the ROLE role.

Commands:
2.12. OProfile OProfile is a system-wide performance monitoring tool. It uses the processor's dedicated performance monitoring hardware to retrieve information about the kernel and system executables to determine the frequency of certain events, such as when memory is referenced, the number of second-level cache requests, and the number of hardware requests received. OProfile can also be used to determine processor usage, and to determine which applications and services are used most often. However, OProfile does have several limitations: Performance monitoring samples may not be precise. Because the processor may execute instructions out of order, samples can be recorded from a nearby instruction instead of the instruction that triggered the interrupt. OProfile expects processes to start and stop multiple times. As such, samples from multiple runs are allowed to accumulate. You may need to clear the sample data from runs. OProfile focuses on identifying problems with processes limited by CPU access. It is therefore not useful for identifying processes that are sleeping while they wait for locks on other events. For more detailed information about OProfile, see Section A.14, "OProfile" , or the Red Hat Enterprise Linux 7 System Administrator's Guide . Alternatively, refer to the documentation on your system, located in /usr/share/doc/oprofile- version .

Commands:
11.4. Configuring Clustered Services The IdM server is not cluster aware . However, it is possible to configure a clustered service to be part of IdM by synchronizing Kerberos keys across all of the participating hosts and configuring services running on the hosts to respond to whatever names the clients use. Enroll all of the hosts in the cluster into the IdM domain. Create any service principals and generate the required keytabs. Collect any keytabs that have been set up for services on the host, including the host keytab at /etc/krb5.keytab . Use the ktutil command to produce a single keytab file that contains the contents of all of the keytab files. For each file, use the rkt command to read the keys from that file. Use the wkt command to write all of the keys which have been read to a new keytab file. Replace the keytab files on each host with the newly-created combined keytab file. At this point, each host in this cluster can now impersonate any other host. Some services require additional configuration to accommodate cluster members which do not reset hostnames when taking over a failed service. For sshd , set GSSAPIStrictAcceptorCheck no in /etc/ssh/sshd_config . For mod_auth_kerb , set KrbServiceName Any in /etc/httpd/conf.d/auth_kerb.conf . Note For SSL servers, the subject name or a subject alternative name for the server's certificate must appear correct when a client connects to the clustered host. If possible, share the private key among all of the hosts. If each cluster member contains a subject alternative name which includes the names of all the other cluster members, that satisfies any client connection requirements.

Commands:
Power Management Guide Red Hat Enterprise Linux 6 Managing power consumption on Red Hat Enterprise Linux 6 Red Hat Inc. Edited by Marie Dolezelova Red Hat Customer Content Services mdolezel@redhat.com Jaroslav Skarvada Red Hat Developer Experience jskarvad@redhat.com Jana Heves Red Hat Customer Content Services Yoana Ruseva Red Hat Customer Content Services Jack Reed Red Hat Customer Content Services Rudiger Landmann Red Hat Customer Content Services Don Domingo Red Hat Customer Content Services

Commands:
Chapter 4. Disabling monitoring for user-defined projects As a dedicated-admin , you can disable monitoring for user-defined projects. You can also exclude individual projects from user workload monitoring. 4.1. Disabling monitoring for user-defined projects By default, monitoring for user-defined projects is enabled. If you do not want to use the built-in monitoring stack to monitor user-defined projects, you can disable it. Prerequisites You logged in to OpenShift Cluster Manager . Procedure From the OpenShift Cluster Manager Hybrid Cloud Console, select a cluster. Click the Settings tab. Click the Enable user workload monitoring check box to unselect the option, and then click Save . User workload monitoring is disabled. The Prometheus, Prometheus Operator, and Thanos Ruler components are stopped in the openshift-user-workload-monitoring project. 4.2. Excluding a user-defined project from monitoring Individual user-defined projects can be excluded from user workload monitoring. To do so, add the openshift.io/user-monitoring label to the project's namespace with a value of false . Procedure Add the label to the project namespace: USD oc label namespace my-project 'openshift.io/user-monitoring=false' To re-enable monitoring, remove the label from the namespace: USD oc label namespace my-project 'openshift.io/user-monitoring-' Note If there were any active monitoring targets for the project, it may take a few minutes for Prometheus to stop scraping them after adding the label.

Commands:
oc label namespace my-project 'openshift.io/user-monitoring=false'
oc label namespace my-project 'openshift.io/user-monitoring-'