The Source-to-Image (S2I) toolkit allows you to easily build application container images for OpenShift deployment. Red Hat provides S2I images for a number of languages including Node.js. For example, this is the image for Node.js 16.x. To learn more about using the Red Hat images versus other Node.js images, check out the Building good containers section of the Node.js reference architecture.
If you have an application with a
package.json that includes an
npm start command, deploying that application using nodeshift (which supports S2I) can be as easy as running
nodeshift in the directory with the
package.json. It will package your application and deploy to your current OpenShift project.
Super easy, right? Well, most of the time. It might get a bit more complicated if your application uses native add-ons that need additional libraries not installed in the Node.js container image. For example, if you want to use the odbc package, you will need some ODBC libraries and the odbc client for the database you want to connect to. More specifically, if you want to use the odbc package with the MySQL database, install the additional libraries through the following RPMs:
So how do you pull all this off? The following steps worked for me:
- Building an image that extends the Node.js container image by adding the required RPMs.
- Deploying the application with Nodeshift and instructing it to use this image.
We'll dive into these steps over the remainder of this article to show you how it's done.
Build the extended image
I used a
BuildConfig to build the extended image:
apiVersion: build.openshift.io/v1 kind: BuildConfig metadata: name: odbc-base spec: source: dockerfile: | FROM registry.access.redhat.com/ubi8/nodejs-16 USER 0 RUN curl https://repo.mysql.com/mysql80-community-release-el8-1.noarch.rpm >mysql80-community-release-el8-1.noarch.rpm RUN dnf localinstall -y mysql80-community-release-el8-1.noarch.rpm RUN dnf install --nogpgcheck -y unixODBC mysql-connector-odbc RUN sed -i -e 's|Driver64=/usr/lib64/libmyodbc5.so|Driver64=/usr/lib64/libmyodbc8w.so|g' /etc/odbcinst.ini USER 1001 strategy: type: Docker output: to: kind: ImageStreamTag name: odbc-base:latest
I saved that in
odbc-base.yaml and applied it with:
oc apply -f odbc-base.yaml
This creates a new OpenShift ImageStream named
odbc-base, which extends the base Node.js image (in the
FROM line) by installing the
mysql-connector-odbc RPMs (
RUN dnf install --nogpgcheck -y unixODBC mysql-connector-odbc). The rest of the lines in the Dockerfile are either set up to make the RPMs available or a workaround for what appears to be a bug in the
USER 0 and
USER 1001 lines are needed to set the user to root so that the
dnf commands can run, and then to set the user back to what is expected by the S2I image when it runs.
localinstall commands are needed to add the repository from which the
mysql-connector-odbc RPM comes.
sed command works around a bug in the
mysql-connector-odbc install where the
odbcinst.ini configuration file points to the wrong library for MySQL in the default install.
Once I applied the build config with
oc apply -f odbc-base.yaml, I completed the following steps as an Administrator in the OpenShift GUI:
- Create an image stream named
odbc-base. If you don’t do this, the build in step 2 will wait for the image stream before starting.
- Start a build for the build config making
Deploy with the extended image
Once you have the extended image in OpenShift as the
odbc-base image stream, deploy it as follows:
If you ever wondered how to handle Node.js packages that require additional system libraries using S2I, I hope this article has helped. Only a few additional steps are required, and you are back to a single nodeshift install.