mtpti5iD/redhat-docs_dataset huggingface dataset:
2.3.4. Snapshot Volumes The LVM snapshot feature provides the ability to create virtual images of a device at a particular instant without causing a service interruption. When a change is made to the original device (the origin) after a snapshot is taken, the snapshot feature makes a copy of the changed data area as it was prior to the change so that it can reconstruct the state of the device. Note LVM snapshots are not supported across the nodes in a cluster. Because a snapshot copies only the data areas that change after the snapshot is created, the snapshot feature requires a minimal amount of storage. For example, with a rarely updated origin, 3-5 % of the origin's capacity is sufficient to maintain the snapshot. Note Snapshot copies of a file system are virtual copies, not actual media backup for a file system. Snapshots do not provide a substitute for a backup procedure. The size of the snapshot governs the amount of space set aside for storing the changes to the origin volume. For example, if you made a snapshot and then completely overwrote the origin the snapshot would have to be at least as big as the origin volume to hold the changes. You need to dimension a snapshot according to the expected level of change. So for example a short-lived snapshot of a read-mostly volume, such as /usr , would need less space than a long-lived snapshot of a volume that sees a greater number of writes, such as /home . If a snapshot runs full, the snapshot becomes invalid, since it can no longer track changes on the origin volumed. You should regularly monitor the size of the snapshot. Snapshots are fully resizeable, however, so if you have the storage capacity you can increase the size of the snapshot volume to prevent it from getting dropped. Conversely, if you find that the snapshot volume is larger than you need, you can reduce the size of the volume to free up space that is needed by other logical volumes. When you create a snapshot file system, full read and write access to the origin stays possible. If a chunk on a snapshot is changed, that chunk is marked and never gets copied from the original volume. There are several uses for the snapshot feature: Most typically, a snapshot is taken when you need to perform a backup on a logical volume without halting the live system that is continuously updating the data. You can execute the fsck command on a snapshot file system to check the file system integrity and determine whether the original file system requires file system repair. Because the snapshot is read/write, you can test applications against production data by taking a snapshot and running tests against the snapshot, leaving the real data untouched. You can create volumes for use with the Xen virtual machine monitor. You can use the snapshot feature to create a disk image, snapshot it, and modify the snapshot for a particular domU instance. You can then create another snapshot and modify it for another domU instance. Since the only storage used is chunks that were changed on the origin or snapshot, the majority of the volume is shared.

Commands:
Chapter 60. JmxTransOutputDefinitionTemplate schema reference Used in: JmxTransSpec Property Property type Description outputType string Template for setting the format of the data that will be pushed.For more information see JmxTrans OutputWriters . host string The DNS/hostname of the remote host that the data is pushed to. port integer The port of the remote host that the data is pushed to. flushDelayInSeconds integer How many seconds the JmxTrans waits before pushing a new set of data out. typeNames string array Template for filtering data to be included in response to a wildcard query. For more information see JmxTrans queries . name string Template for setting the name of the output definition. This is used to identify where to send the results of queries should be sent.

Commands:
4.2. Cloning a Virtual Machine Before proceeding with cloning, shut down the virtual machine. You can clone the virtual machine using virt-clone or virt-manager . 4.2.1. Cloning Guests with virt-clone You can use virt-clone to clone virtual machines from the command line. Note that you need root privileges for virt-clone to complete successfully. The virt-clone command provides a number of options that can be passed on the command line. These include general options, storage configuration options, networking configuration options, and miscellaneous options. Only the --original is required. To see a complete list of options, enter the following command: The virt-clone man page also documents each command option, important variables, and examples. The following example shows how to clone a guest virtual machine called "demo" on the default connection, automatically generating a new name and disk clone path. Example 4.1. Using virt-clone to clone a guest # virt-clone --original demo --auto-clone The following example shows how to clone a QEMU guest virtual machine called "demo" with multiple disks. Example 4.2. Using virt-clone to clone a guest # virt-clone --connect qemu:///system --original demo --name newdemo --file /var/lib/libvirt/images/newdemo.img --file /var/lib/libvirt/images/newdata.img 4.2.2. Cloning Guests with virt-manager This procedure describes cloning a guest virtual machine using the virt-manager utility. Procedure 4.2. Cloning a Virtual Machine with virt-manager Open virt-manager Start virt-manager . Launch the Virtual Machine Manager application from the Applications menu and System Tools submenu. Alternatively, run the virt-manager command as root. Select the guest virtual machine you want to clone from the list of guest virtual machines in Virtual Machine Manager . Right-click the guest virtual machine you want to clone and select Clone . The Clone Virtual Machine window opens. Figure 4.1. Clone Virtual Machine window Configure the clone To change the name of the clone, enter a new name for the clone. To change the networking configuration, click Details . Enter a new MAC address for the clone. Click OK . Figure 4.2. Change MAC Address window For each disk in the cloned guest virtual machine, select one of the following options: Clone this disk - The disk will be cloned for the cloned guest virtual machine Share disk with guest virtual machine name - The disk will be shared by the guest virtual machine that will be cloned and its clone Details - Opens the Change storage path window, which enables selecting a new path for the disk Figure 4.3. Change storage path window Clone the guest virtual machine Click Clone .

Commands:
virt-clone --help
4.2. Launching the Smart Card Manager UI There are two aspects to launching the Enterprise Security Client UI. The Enterprise Security Client process must be started and it runs silently, waiting to detect any inserted smart card or token. The Smart Card Manager UI for the Enterprise Security Client opens automatically when smart cards are inserted or can be opened manually. Initiate the Enterprise Security Client daemon ( escd ) from the command line: This daemon listens silently for smart cards and opens the GUI as soon as a smart card is inserted. To open the Smart Card Manager GUI manually, click Applications , System Tools , and then Smart Card Manager . Figure 4.1. Selecting the Smart Card Manager Item in the Menu

Commands:
esc
Chapter 29. Overview of NVMe over fabric devices Non-volatile Memory Express (NVMe) is an interface that allows host software utility to communicate with solid state drives. Use the following types of fabric transport to configure NVMe over fabric devices: NVMe over fabrics using Remote Direct Memory Access (RDMA). For information on how to configure NVMe/RDMA, see Section 29.1, "NVMe over fabrics using RDMA" . NVMe over fabrics using Fibre Channel (FC). For information on how to configure FC-NVMe, see Section 29.2, "NVMe over fabrics using FC" . When using FC and RDMA, the solid-state drive does not have to be local to your system; it can be configured remotely through a FC or RDMA controller. 29.1. NVMe over fabrics using RDMA The following sections describe how to deploy an NVMe over RDMA (NVMe/RDMA) initiator configuration. 29.1.1. Configuring an NVMe over RDMA client Use this procedure to configure an NVMe/RDMA client using the NVMe management command line interface ( nvme-cli ). Install the nvme-cli package: Load the nvme-rdma module if it is not loaded: Discover available subsystems on the NVMe target: Connect to the discovered subsystems: Replace testnqn with the NVMe subsystem name. Replace 172.31.0.202 with the target IP address. Replace 4420 with the port number. List the NVMe devices that are currently connected: Optional: Disconnect from the target: Additional resources For more information, see the nvme man page and the NVMe-cli Github repository .

Commands:
yum install nvme-cli
modprobe nvme-rdma
nvme discover -t rdma -a 172.31.0.202 -s 4420 Discovery Log Number of Records 1, Generation counter 2 =====Discovery Log Entry 0====== trtype: rdma adrfam: ipv4 subtype: nvme subsystem treq: not specified, sq flow control disable supported portid: 1 trsvcid: 4420 subnqn: testnqn traddr: 172.31.0.202 rdma_prtype: not specified rdma_qptype: connected rdma_cms: rdma-cm rdma_pkey: 0x0000
nvme connect -t rdma -n testnqn -a 172.31.0.202 -s 4420 # lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 465.8G 0 disk ├─sda1 8:1 0 1G 0 part /boot └─sda2 8:2 0 464.8G 0 part ├─rhel_rdma--virt--03-root 253:0 0 50G 0 lvm / ├─rhel_rdma--virt--03-swap 253:1 0 4G 0 lvm [SWAP] └─rhel_rdma--virt--03-home 253:2 0 410.8G 0 lvm /home nvme0n1 # cat /sys/class/nvme/nvme0/transport rdma
nvme list
nvme disconnect -n testnqn NQN:testnqn disconnected 1 controller(s) # lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 465.8G 0 disk ├─sda1 8:1 0 1G 0 part /boot └─sda2 8:2 0 464.8G 0 part ├─rhel_rdma--virt--03-root 253:0 0 50G 0 lvm / ├─rhel_rdma--virt--03-swap 253:1 0 4G 0 lvm [SWAP] └─rhel_rdma--virt--03-home 253:2 0 410.8G 0 lvm /home
function::usecs_to_string Name function::usecs_to_string - Human readable string for given microseconds Synopsis Arguments usecs Number of microseconds to translate. Description Returns a string representing the number of microseconds as a human readable string consisting of " XmY.ZZZZZZs " , where X is the number of minutes, Y is the number of seconds and ZZZZZZ is the number of microseconds.

Commands:
usecs_to_string:string(usecs:long)
23.6. Partition and File System Tools This section describes how different partition and file system management tools interact with a device's I/O parameters. util-linux-ng's libblkid and fdisk The libblkid library provided with the util-linux-ng package includes a programmatic API to access a device's I/O parameters. libblkid allows applications, especially those that use Direct I/O, to properly size their I/O requests. The fdisk utility from util-linux-ng uses libblkid to determine the I/O parameters of a device for optimal placement of all partitions. The fdisk utility will align all partitions on a 1MB boundary. parted and libparted The libparted library from parted also uses the I/O parameters API of libblkid . Anaconda , the Red Hat Enterprise Linux 7 installer, uses libparted , which means that all partitions created by either the installer or parted will be properly aligned. For all partitions created on a device that does not appear to provide I/O parameters, the default alignment will be 1MB. The heuristics parted uses are as follows: Always use the reported alignment_offset as the offset for the start of the first primary partition. If optimal_io_size is defined (i.e. not 0 ), align all partitions on an optimal_io_size boundary. If optimal_io_size is undefined (i.e. 0 ), alignment_offset is 0 , and minimum_io_size is a power of 2, use a 1MB default alignment. This is the catch-all for "legacy" devices which don't appear to provide I/O hints. As such, by default all partitions will be aligned on a 1MB boundary. Note Red Hat Enterprise Linux 7 cannot distinguish between devices that don't provide I/O hints and those that do so with alignment_offset=0 and optimal_io_size=0 . Such a device might be a single SAS 4K device; as such, at worst 1MB of space is lost at the start of the disk. File System Tools The different mkfs. filesystem utilities have also been enhanced to consume a device's I/O parameters. These utilities will not allow a file system to be formatted to use a block size smaller than the logical_block_size of the underlying storage device. Except for mkfs.gfs2 , all other mkfs. filesystem utilities also use the I/O hints to layout on-disk data structure and data areas relative to the minimum_io_size and optimal_io_size of the underlying storage device. This allows file systems to be optimally formatted for various RAID (striped) layouts.

Commands:
B.73.2. RHSA-2011:0197 - Moderate: postgresql security update Updated postgresql packages that fix one security issue are now available for Red Hat Enterprise Linux 4, 5, and 6. The Red Hat Security Response Team has rated this update as having moderate security impact. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) associated with each description below. PostgreSQL is an advanced object-relational database management system (DBMS). CVE-2010-4015 A stack-based buffer overflow flaw was found in the way PostgreSQL processed certain tokens from an SQL query when the intarray module was enabled on a particular database. An authenticated database user running a specially-crafted SQL query could use this flaw to cause a temporary denial of service (postgres daemon crash) or, potentially, execute arbitrary code with the privileges of the database server. Red Hat would like to thank Geoff Keating of the Apple Product Security team for reporting this issue. For Red Hat Enterprise Linux 4, the updated postgresql packages contain a backported patch for this issue; there are no other changes. For Red Hat Enterprise Linux 5, the updated postgresql packages upgrade PostgreSQL to version 8.1.23, and contain a backported patch for this issue. Refer to the PostgreSQL Release Notes for a full list of changes: http://www.postgresql.org/docs/8.1/static/release.html For Red Hat Enterprise Linux 6, the updated postgresql packages upgrade PostgreSQL to version 8.4.7, which includes a fix for this issue. Refer to the PostgreSQL Release Notes for a full list of changes: http://www.postgresql.org/docs/8.4/static/release.html All PostgreSQL users are advised to upgrade to these updated packages, which correct this issue. If the postgresql service is running, it will be automatically restarted after installing this update.

Commands:
3.2. Cloning a Virtual Machine Before proceeding with cloning, shut down the virtual machine. You can clone the virtual machine using virt-clone or virt-manager . 3.2.1. Cloning Guests with virt-clone You can use virt-clone to clone virtual machines from the command line. Note that you need root privileges for virt-clone to complete successfully. The virt-clone command provides a number of options that can be passed on the command line. These include general options, storage configuration options, networking configuration options, and miscellaneous options. Only the --original is required. To see a complete list of options, enter the following command: The virt-clone man page also documents each command option, important variables, and examples. The following example shows how to clone a guest virtual machine called "demo" on the default connection, automatically generating a new name and disk clone path. Example 3.1. Using virt-clone to clone a guest # virt-clone --original demo --auto-clone The following example shows how to clone a QEMU guest virtual machine called "demo" with multiple disks. Example 3.2. Using virt-clone to clone a guest # virt-clone --connect qemu:///system --original demo --name newdemo --file /var/lib/xen/images/newdemo.img --file /var/lib/xen/images/newdata.img

Commands:
virt-clone --help
Chapter 12. TLS-e for DCN You can enable TLS (transport layer security) on clouds designed for distributed compute node infrastructure. You have the option of either enabling TLS for public access only, or enabling TLS on every network with TLS-e, which allows for encryption on all internal and external dataflows. You cannot enable public access on edge stacks as edge sites do not have public endpoints. For more information on TLS for public access, see Enabling SSL/TLS on Overcloud Public Endpoints . 12.1. Deploying distributed compute node architecture with TLS-e Prerequisites When you configure TLS-e on Red Hat OpenStack Platform (RHOSP) distributed compute node architecture with Red Hat Identity Manager (IdM), take the following actions based on the version of Red Hat Enterprise Linux deployed for Red Hat Identity Manager. Red Hat Enterprise Linux 8.4 On the Red Hat Identity Management node, allowed trusted subnets to an ACL In the ipa-ext.conf file: In the /etc/named/ipa-options-ext.conf file, allow recursion, and query cache: Restart the `named-pkcs11 service: Red Hat Enterprise Linux 8.2 If you have Red Hat Identity Manager (IdM) on Red Hat Enterprise Linux (RHEL) 8.2, you must upgrade Red Hat Enterprise Linux and then follow the directions for RHEL 8.4 Red Hat Enterprise Linux 7.x If you have Red Hat Identity Manager (IdM) on Red Hat Enterprise Linux (RHEL) 7.x, you must add an access control instruction (ACI) for your domain name manually. For example, if the domain name is redhat.local , run the following commands on Red Hat Identity Manager to configure the ACI: Due to differences in design between the central and edge locations, do not include the following files in edge stacks: tls-everywhere-endpoints-dns.yaml This file is ignored at edge sites, the endpoints that it sets are overridden by the endpoints exported from the central stack. haproxy-public-tls-certmonger.yaml This file causes a failed deployment as there are no public endpoints at the edge. Additional information: Implementing TLS-e with Ansible

Commands:
acl "trusted_network" { localnets; localhost; 192.168.24.0/24; 192.168.25.0/24; };
allow-recursion { trusted_network; }; allow-query-cache { trusted_network; };
systemctl restart named-pkcs11
ADMIN_PASSWORD=redhat_01 DOMAIN_LEVEL_1=local DOMAIN_LEVEL_2=redhat cat << EOF | ldapmodify -x -D "cn=Directory Manager" -w USD{ADMIN_PASSWORD} dn: cn=dns,dc=USD{DOMAIN_LEVEL_2},dc=USD{DOMAIN_LEVEL_1} changetype: modify add: aci aci: (targetattr = "aaaarecord || arecord || cnamerecord || idnsname || objectclass || ptrrecord")(targetfilter = "(&(objectclass=idnsrecord)(|(aaaarecord=)(arecord=)(cnamerecord=)(ptrrecord=)(idnsZoneActive=TRUE)))")(version 3.0; acl "Allow hosts to read DNS A/AAA/CNAME/PTR records"; allow (read,search,compare) userdn = "ldap:///fqdn=*,cn=computers,cn=accounts,dc=USD{DOMAIN_LEVEL_2},dc=USD{DOMAIN_LEVEL_1}";) EOF
Chapter 3. Installing Windows Virtual Machines This chapter describes the steps required to install a Windows virtual machine: Create a blank virtual machine on which to install an operating system. Add a virtual disk for storage. Add a network interface to connect the virtual machine to the network. Attach the virtio-win.vfd diskette to the virtual machine so that VirtIO-optimized device drivers can be installed during the operating system installation. Install an operating system on the virtual machine. See your operating system's documentation for instructions. Install guest agents and drivers for additional virtual machine functionality. When all of these steps are complete, the new virtual machine is functional and ready to perform tasks. 3.1. Creating a Virtual Machine Create a new virtual machine and configure the required settings. Procedure You can change the default virtual machine name length with the engine-config tool. Run the following command on the Manager machine: Click Compute Virtual Machines . Click New to open the New Virtual Machine window. Select an Operating System from the drop-down list. Enter a Name for the virtual machine. Add storage to the virtual machine. Attach or Create a virtual disk under Instance Images . Click Attach and select an existing virtual disk. Click Create and enter a Size(GB) and Alias for a new virtual disk. You can accept the default settings for all other fields, or change them if required. See Section A.4, "Explanation of Settings in the New Virtual Disk and Edit Virtual Disk Windows" for more details on the fields for all disk types. Connect the virtual machine to the network. Add a network interface by selecting a vNIC profile from the nic1 drop-down list at the bottom of the General tab. Specify the virtual machine's Memory Size on the System tab. Choose the First Device that the virtual machine will boot from on the Boot Options tab. You can accept the default settings for all other fields, or change them if required. For more details on all fields in the New Virtual Machine window, see Section A.1, "Explanation of Settings in the New Virtual Machine and Edit Virtual Machine Windows" . Click OK . The new virtual machine is created and displays in the list of virtual machines with a status of Down . Before you can use this virtual machine, you must install an operating system and VirtIO-optimized disk and network drivers.

Commands:
engine-config --set MaxVmNameLength= integer
9.8. Securing NFS NFS is well-suited for sharing entire file systems with a large number of known hosts in a transparent manner. However, with ease-of-use comes a variety of potential security problems. Consider the following sections when exporting NFS file systems on a server or mounting them on a client. Doing so minimizes NFS security risks and better protects data on the server. 9.8.1. NFS Security with AUTH_SYS and export controls Traditionally, NFS has given two options in order to control access to exported files. First, the server restricts which hosts are allowed to mount which filesystems either by IP address or by host name. Second, the server enforces file system permissions for users on NFS clients in the same way it does local users. Traditionally it does this using AUTH_SYS (also called AUTH_UNIX ) which relies on the client to state the UID and GID's of the user. Be aware that this means a malicious or misconfigured client can easily get this wrong and allow a user access to files that it should not. To limit the potential risks, administrators often allow read-only access or squash user permissions to a common user and group ID. Unfortunately, these solutions prevent the NFS share from being used in the way it was originally intended. Additionally, if an attacker gains control of the DNS server used by the system exporting the NFS file system, the system associated with a particular hostname or fully qualified domain name can be pointed to an unauthorized machine. At this point, the unauthorized machine is the system permitted to mount the NFS share, since no username or password information is exchanged to provide additional security for the NFS mount. Wildcards should be used sparingly when exporting directories through NFS, as it is possible for the scope of the wildcard to encompass more systems than intended. It is also possible to restrict access to the rpcbind [3] service with TCP wrappers. Creating rules with iptables can also limit access to ports used by rpcbind , rpc.mountd , and rpc.nfsd . For more information on securing NFS and rpcbind , refer to man iptables .

Commands:
6.2.2. Creating the Volume Group The following command creates the volume group volgroup01 . You can use the vgs command to display the attributes of the new volume group.

Commands:
vgcreate volgroup01 /dev/sda1 /dev/sdb1 /dev/sdc1 Volume group "volgroup01" successfully created
vgs VG #PV #LV #SN Attr VSize VFree volgroup01 3 0 0 wz--n- 51.45G 51.45G