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Author: Albert

How to calculate memory assigned for nodes in a cluster

Run the following command to calculate the currently used memory (megabytes) in openshift container platform 4.x. oc adm top node | awk '{ sum+=$4} END {print sum}' Run the following command to calculate the used memory (megabytes) for worker nodes in the cluster. oc adm top node --selector='node-role.kubernetes.io/worker=' | awk '{ sum+=$4} END {print sum}' …

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How do change the location of /var/log/squid/squid.out file?

To change the location of squid.out file, copy /usr/libexec/squid/cache_swap.sh to a new location. # cp /usr/libexec/squid/cache_swap.sh /usr/libexec/squid/cust_cache_swap.sh Open with vi and edit the following section in the new file cust_cache_swap.sh. squid -N -z -F -f $SQUID_CONF >> /new/path/to/squid.out 2>&1 Copy the unit file of squid.service as follows. # cp /usr/lib/systemd/system/squid.service /etc/systemd/system/ Edit /etc/systemd/system/squid.service. (before) ExecStartPre=/usr/libexec/squid/cache_swap.sh …

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Why packets drops against ‘rx_fifo_errors’ parameter in the output of ‘ethtool -S ‘ ?

The output of ethtool -S <interface> reveals receive fifo errors. Additionally, rx_queue_<n>_drops, the total of which equals the value of rx_fifo_errors, are reported. # ethtool -S eth0 | egrep 'rx_fifo|drops' rx_fifo_errors: 120674 rx_queue_0_drops: 4032 rx_queue_1_drops: 3036 rx_queue_2_drops: 5904 rx_queue_3_drops: 0 rx_queue_4_drops: 228 rx_queue_5_drops: 65656 rx_queue_6_drops: 19267 rx_queue_7_drops: 22551 # ethtool -S eth0 | egrep drops …

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Why Ansible Engine / Tower job fail with ‘Server not found in Kerberos database’ Error ?

My playbook job fails with the error “Server not found in Kerberos database” when executed against a Windows server with Kerberos authentication. TASK [Ping host] ****************************************************************************************************************************************************************************************** fatal: [host01.mydomain.com]: UNREACHABLE! => {"changed": false, "msg": "kerberos: authGSSClientStep() failed: (('Unspecified GSS failure. Minor code may provide more information', 851968), ('Server not found in Kerberos database', -1765328377))", "unreachable": true} …

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Failed to create notification semaphore: Invalid argument – LVM error

lvcreate gives the following error about semaphore. lvcreate -n test_lv10 -L 1G test_vg_3 Found duplicate PV XfbmuZ2c2MPAb8r0TDIBNrcyUx0yMZpu: using /dev/emcpowerh not /dev/sdb Failed to create notification semaphore: Invalid argument Unable to resume test_vg_3-test_lv10 (253:3) Failed to activate new LV. Failed to create notification semaphore: Invalid argument Unable to deactivate test_vg_3-test_lv10 (253:3) Unable to deactivate failed new …

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How to create LVM snapshot for system maintenance?

This article shows step-by-step instructions for getting a CentOS system ready and making LVM snapshots for system maintenance or software upgrades. LVM snapshots are meant to be used as a restoration point if anything goes wrong during the upgrade process. The suggestion is to run this procedure in a test environment first. Also, one of …

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How to shrink an LVM Logical Volume

Since shrinking is not supported on these file systems, you cannot reduce the size of a logical volume that houses a GFS2 or XFS file system. The lvreduce command typically warns about potential data loss and requests confirmation. In some circumstances, such as when the logical volume is inactive, or the —resizefs option is not …

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