To configure Azure Redis with the VNET support, we can follow the steps described in this document. And to integrate Azure web app with a VNET, there is a detailed document for it as well. In this post, I listed some of the common issues that one might hit during the configuration.
The VNET integration for Azure Redis requires an empty subnet for the VNET that is created with Resource Manager. This subnet needs to be created before you create Azure Redis. Otherwise, the configuration would fail.
The subnet for Azure Redis can be protected with a network security group (NSG). Usually the default NSG rules are good enough for protecting the connections. If you need further hardening, you will have to create rules based on the ports list in the Azure Redis document.
To troubleshoot the connection between Azure web app and Azure Redis, you can use the Kudu of web app. There are two tools built in with the web app for network troubleshooting: nameresolver.exe can be used to test the DNS functionalities, and tcpping.execan be used to test if the host and port can be pinged. But you cannot test the Redis function directly from the Kudu.
Once the VNET integration is configured, the Redis console in Azure Portal will not work anymore. To test the Redis functions with tools such as redis-cli, you will have to build a VM in the VNET and connect to Azure Redis from it.
If somehow your web app cannot access the Azure Redis, although the network configurations are correct, you can try to sync the network for App Service Plan. See this issue for details. Make sure you don’t hit any error when syncing the network.
Today I finally decided to move this site from its old domain to this new one, chunliu.me, which I got last year. For a personal hosted WordPress site, changing domain name is not a straight forward task, especially when you don’t want to break the existing external links that point to the site. Here is how I did it, with a lot of search on internet of course.
Copy the database and WordPress folder
To minimize the impact to the existing site, I duplicated the MySQL database of this site and its WordPress folder. Copy WordPress folder is easy, simply use cp command to copy the whole folder. Copy database is a bit tricky because I forgot the password of the MySQL root user. I used the following way to reset the password of the root user.
Run mysql with --skip-grant-tables.
$ sudo service mysql stop
$ sudo mkdir -p /var/run/mysqld
$ sudo chown mysql:mysql /var/run/mysqld
$ sudo mysqld --skip-grant-tables --skip-networking &
Update the password of root user with mysql client.
$ mysql -u root
mysql> FLUSH PRIVILEGES;
mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'MyNewPass';
Restart mysql service.
$ sudo pkill mysqld
$ sudo service mysql start
With the above steps, the database can be copied with the following command.
Azure Pipelines has the very good integration with GitHub. It provides 10 free parallel jobs and unlimited minutes for open source projects. It is a very good choice for open source projects to have the CI/CD capability.
As I have configured the site to use hexo’s git deployment, an Azure build pipeline is enough to carry out the deployment. And in the build pipeline, I need the following three tasks.
Install all npm packages used by the site with npm install.
Configure git credential and run hexo deploy.
The first 2 steps are quite straight forward. The tricky part is how to use script to configure git credentials. git credential store only accept inputs from stdin. I did some search and tests, and ended up with a bash pipe to feed in the credentials. The following is a sample for credential store.
As credential store will save the credential to a file on disk, it is not a good practice for a shared build agent. I ended up to replace the credential store with credential cache, and exit the cache when deployment is done.
The following is the yaml file of the build definition. $GHP is an environment variable storing the personal token of GitHub. The actual value is saved in Azure DevOps encrypted.
I recently played with Java and Azure App Service. What I was trying to find out is how the development experience would look like for Java developers if they want to build their applications with Azure App Service and Azure Database for MySQL.
There are some documents on Microsoft doc site, such as this one. It might be good enough for an experienced Java developer, but for someone like me who has limit Java experience, it is not easy to follow, and the sample is also too simple to make any sense for a real development. So I decided to try it myself and documented my experience here for others to reference. There would be a series of posts, and this is the first one.
Prepare the dev environment
So instead of installing IntelliJ or Eclipse, I choose to use VSCode as my Java IDE. On my computer I’ve already had the VSCode installed. According to this tutorial, I just need to install JDK and Maven. I am a bit lost with the Java terms like Java SE, JDK, JRE and their versions, but I don’t want to be bothered. I choose to install OpenJDK because Oracle JDK requires a license. So here are steps to install OpenJDK.
Download OpenJDK from here. Windows version of OpenJDK is a zip file. Unzip it to C:\Program Files\Java so the root fold of the JDK would be something like C:\Program Files\Java\jdk-11.0.1
Add an environment variable JAVA_HOME, set its value to the root of the JDK, for example, C:\Program Files\Java\jdk-11.0.1
Add C:\Program Files\Java\jdk-11.0.1\bin to the system path.
With the above steps, OpenJDK is installed completely. To test if it works, open a command window and run java -version. It should print out the OpenJDK version and runtime information.
When OpenJDK is installed, you can follow the vscode tutorial to download and install maven, and the Java Extension Pack for vscode.
Create a MySQL database
Instead of installing MySQL on my local computer, I choose to create an Azure Database for MySQL instance as the dev database environment. It is easy to provision an Azure Database for MySQL instance. Azure has quick start for it. I also run the following SQL query to configure the database in Azure Cloud Shell.
CREATE DATABASE tododb; -- Create a database
CREATE USER 'springuser'@'%' IDENTIFIED BY 'Spring1234'; -- Create a database user
GRANT ALL PRIVILEGES ON tododb.* TO 'springuser'@'%'; -- Grant user permissions to the database
With the above preparation, we have a Java development environment and a MySQL database ready for the development. In the next post, I will start to create a Spring Boot REST API app with VSCode. Stay tuned.
I have received several notifications from my Ubuntu server running in Azure for asking me to upgrade the server to Ubuntu 18.04.1. When Ubuntu 18.04 was first released, I didn’t upgrade the server. I was afraid there could be compatibility issues and I don’t want to break the server. With the release of 18.04.1, it seems the version is stable enough for an upgrade. So I decided to upgrade the server.
Here is what I did.
First of all, I updated the server with apt update && apt upgrade, and then I backed up my server with Azure VM backup. In case upgrade failed, I can restore the VM back.
Then I ran do-release-upgrade to upgrade the server. The os kernel seemed to upgrade successfully, but the software package upgrade failed with the following output.
authenticate 'bionic.tar.gz' against 'bionic.tar.gz.gpg'
The upgrade has completed but there were errors during the upgrade
To continue please press [ENTER]
I did some search on the internet. It seems a common issue. To solve this issue, I ran the command sudo mv /usr/share/dbus-1/system-services/org.freedesktop.systemd1.service /usr/share/dbus-1/system-services/org.freedesktop.systemd1.service.bak as it is mentioned here.
After the issue was fixed, I just ran sudo apt-get dist-upgrade to upgrade all packages, and I chose to keep all local copies of configurations. After that, the upgrade completed successfully with all software and services running normally.
From container perspective, Service Fabric is a container orchestrator which supports both Windows and Linux containers. In legacy application lift and shift scenarios, we usually containerize the legacy application with minimal code change. And Service Fabric is a good platform to run these containers.
To deploy a Service Fabric cluster on Azure which is suitable for running containers, we can use ARM template. I created a template with the following special settings:
1 – An additional data disk is attached to the VMs in the cluster to host the downloaded container images. We need this disk is because by default all container images would be downloaded to C drive of the VMs. The C drive may run out of space if there are several large images downloaded.