I started a channel on youtube. The first video series will be about software that helps beginners to start using linux and after this series i will start to talk about my jorney learning new things like OpenShift, IBM Cloud, Cloud Paks and related IBM technologies.
I will record the videos in Brazilian Portuguese first and maybe i will create videos in English.
There is no much content about the things i will record in my native language and not everyone here in Brazil are able listen videos in English.
There is another blog too https://www.chuvisco.net.br were you can view the transcription of the video.
MySphere Posts
We started a CP4D installation on AWS, but without using AWS ROSA. We create a new cluster from scratch.
In our lab everything worked perfectly but when the client went to do its installation the Openshift CLI displayed the following error message:
assertion failed [inst.has.value()]: failed to decode instruction: 0x0
After much analysis, we discovered that the client’s Administrator was using a MacBook Pro M1 laptop.
We found the solution at this link https://veducate.co.uk/
It’s only for messages. No calendar migration
Imapsync command is a tool allowing incremental and recursive imap transfers from one mailbox to another. If you don’t understand the previous sentence, it’s normal, it’s pedantic computer-oriented jargon.
All folders are transferred, recursively, meaning the whole folder hierarchy is taken, all messages in them, and all message flags (\Seen\Answered \Flagged etc.) are synced too.
Imapsync reduces the amount of data transferred by not transferring a given message if it already resides on the destination side. Messages that are on the destination side but not on the source side stay as they are.
Get the tool here https://github.com/imapsync/imapsync
This paper is intended for architects, systems programmers, analysts and programmers wanting to understand the performance characteristics, and best
practises of IBM MQ. The information is not intended as the specification of any programming interface that is provided by IBM. It is assumed that the reader is
familiar with the concepts and operation of IBM MQ.
Link to download the paper: https://ibm-messaging.github.io/mqperf/MQ_Performance_Best_Practices_v1.0.pdf
I received an email yesterday from Docker. It’s a reminder about the end of grace period.
Hello,
As a reminder you’re receiving this email because on August 31, 2021 we updated the terms applicable to the Docker products or services you use.
On January 31, 2022, the grace period ends for free commercial use of Docker Desktop in larger enterprises. Companies with more than 250 employees OR more than $10 million USD in annual revenue now require a paid subscription to use Docker Desktop. Read the blog or visit our FAQ to learn more about these updates.
For me is not a problem anymore i remove Docker Desktop from my computers and install Podman. No issues, no problems everything works.
Don’t need Docker Desktop anymore.
Openshift comes with a set of default templates, you can use
oc get templates -n openshift to show themEach template contains specifc sections
- The objects section: defines a list of resources that will be created
- The parameters section: defines parameters that are used in the template objects
1 – Inspect the template file for the parameters
I export the postgresql-ephemeral to a yaml file using :
oc get template postgresql-ephemeral -o yaml -n openshift > postgresql.yaml Then inspect the yaml file
oc process --parameters -f <filename.yaml>2 – Create the application using oc process
oc process -f postgresql.yaml -l app=mydb -p DATABASE_SERVICE_NAME=dbservice -p POSTGRESQL_USER=dbuser \ -p POSTGRESQL_PASSWORD=password -p POSTGRESQL_DATABASE=books | oc create -f -Podman Pods are very similar to Kubernetes pods in a way that they can have more than one container.
Every Podman pod contains one infra container by default. This container is responsible for associating the names space with the pod and allowing podman to connect the containers to another pod.
Create a Pod using Podman
The first step is to create a Pod using podman:
sudo podman pod create –name <podname>
For our example we will create a pod with the name wp-pod
sudo podman pod create -p 8080:80 --name wp-pod
After creating the Pod you can see the infra container using the command:
sudo podman pod ps -a --pod
Note that host port 8080 has been redirected to port 80 of the pod. Pod port settings should always be made when creating the pod. You cannot reset this later.
Adding containers to a Pod
To add a container to a pod we use the –pod option when using the comand podman run.
sudo podman run -d --name <container name> --pod <podname> <imagename>
Creating a container using the mariadb image
To run the workpress we need a database. In this case I will use the image of mariadb and add it in the pod wp-pod
sudo podman run -d --restart=always –-pod wp-pod \
-e MYSQL_ROOT_PASSWORD="myrootpass" \
-e MYSQL_DATABASE="wpdb" \
-e MYSQL_USER="wpuser" \
-e MYSQL_PASSWORD="w0rdpr3ss" \
--name=wp-db registry.access.redhat.com/rhscl/mariadb-100-rhel7
Next we will create a wordpress container, add it to the pod and connect it to the previously created database.
sudo podman run -d --restart=always --pod wp-pod \
-e WORDPRESS_DB_NAME="wpdb" \
-e WORDPRESS_DB_USER="wpuser" \
-e WORDPRESS_DB_PASSWORD="w0rdpr3ss" \
-e WORDPRESS_DB_HOST="127.0.0.1" --name wp-web wordpress
To verify that if everything is working, run:
curl http://localhost:8080/wp-admin/install.php.
The text corresponding to an html page will appear in the console:
!DOCTYPE html><html lang="en-US" xml:lang="en-US"><head>
<meta name="viewport" content="width=device-width" />
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta name="robots" content="noindex,nofollow" />
<title>WordPress › Installation</title>
<link rel='stylesheet' id='dashicons-css' href='http://localhost:8080/wp-includes/css/dashicons.min.css?ver=5.8.2' type='text/css' media='all' />…
So far, we have a pod with 3 containers: infra, wp-db and wp-web. The pod is running as root and also does not have a volume associated for data persistence.
Rootless Podman
Rootless podman (running Podman as a non-root user) needs to do some gymnastics to get the same container experience you’re familiar with from docker, but without requiring root.
When you run rootless podman, it uses a user namespace to map between the user IDs in the container and the user IDs on your host.
All rootless containers run by you, are run inside the same user namespace.
By using the same user namespace, your containers can share resources with each other, without needing to ask for root privileges.
It uses this user namespace to mount filesystems, or run a container which accesses more than one user ID (UID) or group ID (GID).
This mapping is fine for most situations, except when the container needs to be able to share something with the host, like a volume.
When the container runs, any volumes which are shared with it, will appear inside the user namespace as owned by root/root.
Because the mapping will map your UID on the host (e.g. 1000) as root (0) in the container.
This means that if you’re running your container process as a non-root user, it won’t be able to write to that directory and I don’t want to disable SELinux.
This is where podman unshare comes in.
Running WP-POD as a rootless POD and use a volume to persist data
First we need to create a directory so that it can be used by the container
mkdir /home/<username>/dbfiles
Using the podman inspect command we can see that the mariadb container uses user 27
We then execute the command: podman unshare chown 27:27 -R /home/kenio/dbfiles
To remove the previously created pod:
sudo podman pod stop wp-pod
sudo podman pod rm wp-pod
Perform the following steps to create the wp-pod as rootless:
podman pod create --name=wp-pod -p 8080:80
podman run -d --restart=always \
-v /home/kenio/dbfiles:/var/lib/mysql/data:Z --pod wp-pod \
-e MARIADB_ROOT_PASSWORD="password" \
-e MYSQL_ROOT_PASSWORD="password" \
-e MYSQL_DATABASE="wpdb" \
-e MYSQL_USER="wpuser" \
-e MYSQL_PASSWORD="w0rdpr3ss" \
--name=wp-db registry.access.redhat.com/rhscl/mariadb-100-rhel7
Note that I add the :Z flag to the volume. This tells Podman to label the volume content as “private unshared” with SELinux.
This label allows the container to write to the volume, but doesn’t allow the volume to be shared with other containers.
podman run -d --restart=always --pod=wp-pod \
-e WORDPRESS_DB_NAME="wpdb" \
-e WORDPRESS_DB_USER="wpuser" \
-e WORDPRESS_DB_PASSWORD="w0rdpr3ss" \
-e WORDPRESS_DB_HOST="127.0.0.1" --name wp-web wordpress
Use curl://localhost:8080/wp-admin/install.php and verify if everything is running.
Use podman logs –names <container name> para verificar os logs dos containers
I am using RHEL 8.3 and podman is version 3.2.3
If you want to access the worpress pod from external machine, in my case, I need to setup the firewall:
sudo firewall-cmd --add-port=8080/tcp --permanent
sudo firewall-cmd –reload
Many thanks for Tone Donohue for his article about rootless podman.
https://www.tutorialworks.com/podman-rootless-volumes/
Linux Containers have emerged as a key open source application packaging and delivery technology, combining lightweight application isolation with the flexibility of image-based deployment methods.
Red Hat Enterprise Linux (RHEL) base images are meant to form the foundation for the container images you build. As of April 2019, new Universal Base Image (UBI) versions of RHEL standard, minimal, init, and Red Hat Software Collections images are available that add to those images the ability to be freely redistributed.
RHEL minimal images provide a base for your own container images that is less than half the size of the standard image, while still being able to draw on RHEL software repositories and maintain any compliance requirements your software has.
Building custom images using Containerfile or Dokerfile sometimes you need to install packages on top of the minimal images of RHEL. You need to use microdnf to install things not dnf /yum.
Answer: As minimal as stated: no Python and no Python module dependencies. Which are quite many packages to think of it.
I suppose the actual gap will come also from the fact of not using Python:
- There is no Python interface, and thus you can’t invoke microdnf from a Python code using a consistent API. You’ll have to resort to using the subprocess Python module
- Actual dnf can be expanded with many additional commands provided by the dnf-plugins-core and other plugin packages. You may not expect any of those features in microdnf. They will hardly ever make it to microdnf.
Today I received a notice on my computer about another Docker Desktop update, but this time a new agreement had to be accepted as now for professional use there is a subscription.
I saw many people commenting about this when the new licensing model was announced and since Kubernetes will no longer support the Docker Container Engine, I decided to remove Docker Desktop from my MAC and install Podman.
To remove the Docker Desktop I used this article and to install Podman I used the following steps:
-
brew install podman -
podman machine init -
podman machine start
Use podman info to see if everything is ok.
Today i will install Code Ready. You can install Openshift on your laptop. See this link . My RHEL 8.4 VM has a small disk and first i need to resize the disk and then install CodeReady
Using this commands i change from 20 GB to 50GB disk
First you need to locate the vm disk with the command
sudo virsh domblklist rhel8-1
the output was:
Target Source
——————————————————-
vda /var/lib/libvirt/images/rhel8-2-clone.qcow2
sda –
To resize the disk the VM must be not running and must not have a snapshot.
Just type this command and add 30GB
sudo qemu-img resize /var/lib/libvirt/images/rhel8-2-clone.qcow2 +30G
Start the vm and verify the disk using lsblk command
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sr0 11:0 1 1024M 0 rom
vda 252:0 0 50G 0 disk
|-vda1 252:1 0 1G 0 part /boot
`-vda2 252:2 0 29G 0 part
|-rhel-root 253:0 0 26G 0 lvm /
`-rhel-swap 253:1 0 3G 0 lvm [SWAP]