Archives for May 2021

GCP Instance Scheduler

May 28, 2021

GCP recently added Instance Schedule to its console.

To configure, perform the following.

– Create an instance schedule.
– Add instance(s) to a schedule.
– If no errors, the service account has the correct permissions.

The service account used by Instance Schedule is owned by GCP and is not visible in the GCP console.

If service account has no permissions, the you must perform the following.

– Create a custom role with compute.instances.start and compute.instances.stop permissions.
– Add custom role to the service account.

Finally, validate instances are starting and stopping based on schedule.

Generated by NetworkManager

May 27, 2021

If your /etc/resolv.conf keeps getting overwritten, take a look at /etc/NetworkManager/NetworkManager.conf. Set DNS to none.

[main]
dns=none

GCP Compute Enable OS Login

May 27, 2021

If you have trouble logging in (SSH) to your GCP instance, you may have to enable OS Login.

gcloud compute instances add-metadata server-name \
--metadata enable-oslogin=TRUE \
--zone us-central1-c \
--project project-id

When done, you can set it back to FALSE.

Winbind Fix

May 24, 2021

Here’s the process to restore Winbind.

Restore old config.

cp /etc/sssd/sssd.conf-xxxxxxx /etc/sssd/sssd.conf
cp /etc/krb5.conf-xxxxxxx /etc/krb5.conf

Disable SSSD. Authconfig creates /etc/nswitch.conf.

authconfig --disablesssd --disablesssdauth --updateall

Start Winbind.

service winbind start; service smb start; service nmb start

SSSD Report

May 24, 2021

Generate a SSSD report.

#!/bin/bash
log="log"
> $log
sep () { echo "--------------------------------" >> $log; }
sep
echo "SSSD Status" >> $log
sep
systemctl status sssd >> $log
sep
echo "Contents of /etc/resolv.conf" >> $log
sep
cat /etc/resolv.conf >> $log
sep
echo "Contents of /etc/sssd/sssd.conf" >> $log
sep
cat /etc/sssd/sssd.conf >> $log
sep
echo "Versions of /etc/resolv.conf" >> $log
sep
ls -l /etc/resolv.conf* >> $log
sep
echo "Versions of /etc/sssd/sssd.conf" >> $log
sep
ls -l /etc/sssd/sssd.conf* >> $log
sep
echo "Contents of /var/log/sssd-rollout.log" >> $log
sep
cat /var/log/sssd-rollout.log >> $log
sep
echo "Contents of /var/log/sssd-rollout3.log" >> $log
sep
cat /var/log/sssd-rollout3.log >> $log
sep

Remove SSSD package

May 24, 2021

How to remove SSSD package.

#!/bin/bash
service sssd stop
chkconfig sssd off
rm -rf /var/lib/sss/db/*
rm -f /etc/sssd/sssd.conf
rm -f /etc/krb5.conf
rm -f /etc/krb5.keytab
yum remove -y adcli sssd authconfig pam_krb5 samba4-common realmd

rpmdb open failed

May 22, 2021

If you get this error, something happened to the rpm database. To fix.

rm -f /var/lib/rpm/__db*
db_verify /var/lib/rpm/Packages
rpm --rebuilddb
yum clean all

Run yum again.