Tomcat
CloudCaptain supports Apps written in Java or any other language and packaged as a War file running on either Tomcat 7.x or 8.x using OpenJDK 7, 8, 11, 17 or 21.
Java Runtime Environment
By default CloudCaptain uses the latest OpenJDK 17 version (headless JRE).
OpenJDK version
If you want to switch to OpenJDK 7.x or simply an
older version, you can do so using the -components.openjdk configuration setting:
> boxfuse run my-app-1.0.jar -components.openjdk=7.80.32
To find out which OpenJDK versions are available from the CloudCaptain Inventory you can simply issue:
> boxfuse inventory openjdk
Custom JRE
If you prefer to use a different JRE, including the Oracle JRE, rather than the default OpenJDK one,
you can do so by including the Linux x64 JRE distribution of your choice in a /WEB-INF/jre folder inside the war file.
If you use Maven or Gradle, this means the jre folder should be put into the src/main/webapp/WEB-INF directory:
my-tomcat-app
src
main
java
resources
webapp
WEB-INF
jre
bin
java
...
lib
amd64
...
rt.jar
...
COPYRIGHT
LICENSE
...
Tip for Git users
To avoid file corruption due to Git line-ending normalization, add the following line to .gitattributes
src/main/webapp/WEB-INF/jre/* binary
Tomcat version
By default CloudCaptain uses the latest Tomcat 8.5.x version. If you want to switch to Tomcat 8.0.x,
Tomcat 7.0.x or simply an
older version, you can do so using the -components.tomcat configuration setting:
> boxfuse run my-webapp-1.0.war -components.tomcat=7.0.67
HTTP
By default, CloudCaptain will automatically configure Tomcat to listen to HTTP traffic on port 80.
TLS (SSL) Certificates / HTTPS
Automatic TLS (SSL) Certificate management
To expose your app via HTTPS make sure you have a custom domain configured
for the environment where you want to run it. Also make sure that you have obtained
a valid TLS (SSL) certificate and that your app has been created
with app.type set to load-balanced and tls.type set to acm (AWS Certificate Manager).
With that in place your Tomcat app will be automatically configured to run with HTTPS and a green lock will appear in the browser.
CloudCaptain will ensure that all network traffic between the ELB and your instances will be encrypted as well.
Manual TLS (SSL) Certificate management
To use HTTPS with your own certificate, you first have to obtain a valid certificate from a Certificate Authority and
add a KeyStore containing your SSL certificate inside the .war file as
/WEB-INF/keystore.jks. It must contain a certificate with the alias tomcat and
be secured with the standard password changeit.
CloudCaptain will then automatically configure Tomcat to start serving traffic via HTTPS on port 443, as well as
automatically redirect any insecure HTTP traffic to the secure HTTPS connection.
If you use Maven or Gradle this means you have to put the keystore.jks file under src/main/webapp/WEB-INF:
my-tomcat-app
src
main
java
resources
webapp
WEB-INF
keystore.jks
Root Certificates
By default, CloudCaptain uses the same root certificate bundle as the latest version of Firefox. Additionally CloudCaptain also includes the root certificates for Amazon RDS, so you can connect securely to RDS databases out of the box.
You can, however, ship your own set of root certificates, by placing them in a KeyStore at /WEB-INF/cacerts.
CloudCaptain will then automatically configure both the JRE and Tomcat to use these instead.
If you use Maven or Gradle this means you have to put the cacerts file under src/main/webapp/WEB-INF:
my-tomcat-app
src
main
java
resources
webapp
WEB-INF
cacerts
JCE unlimited strength cryptography
Using CloudCaptain's default JRE
This is already enabled by default (starting with OpenJDK 8.162.12) and no further action is required.
Using an older CloudCaptain JRE
To enable JCE unlimited cryptography (for AES-256, RSA-4096, ...), download the policy zip from the Oracle website for either Java 7 or Java 8.
Extract both local_policy.jar and US_export_policy.jar and place them under /WEB-INF inside your war file.
If you use Maven or Gradle, this means both policy jar files should be put into the src/main/webapp/WEB-INF directory.
CloudCaptain will then automatically configure the JRE to use these instead.
my-tomcat-app
src
main
java
resources
webapp
WEB-INF
local_policy.jar
US_export_policy.jar
Using a custom JRE
If you use a custom JRE it is your responsibility to ensure it is configured for unlimited strength cryptography if you need it.
Custom server.xml (advanced users only)
By default CloudCaptain will auto-generate a server.xml file for Tomcat with sensible defaults and all
connectors set up properly according to the CloudCaptain settings specified.
Sometimes advanced users may want more control over this. CloudCaptain therefore gives you the option to pass in a
custom server.xml file at /WEB-INF/server.xml in your war file.
Note: If you chose to go down this path it is your responsibility to configure all connectors so that they match the CloudCaptain configuration.
If you use Maven or Gradle this means you have to put the server.xml file under src/main/webapp/WEB-INF:
my-tomcat-app
src
main
java
resources
webapp
WEB-INF
server.xml
Databases
Database auto-provisioning
If your app includes the PostgreSQL or MySQL JDBC driver, CloudCaptain will automatically provision the necessary PostgreSQL or MySQL database
in each environment. Note that the JDBC driver jar must be present within your war file under /WEB-INF/lib.
On a Maven or Gradle project this means it should be included as a regular dependency.
When using the CloudCaptain database auto-provisioning support, CloudCaptain automatically
injects environment variables in your instance with the correct details: BOXFUSE_DATABASE_URL (jdbc url),
BOXFUSE_DATABASE_USER (database user) and BOXFUSE_DATABASE_PASSWORD (database password).
This works identically in all environments and CloudCaptain ensures you always get the correct settings.
To configure a Tomcat JDBC DataSource you need a context.xml file under /META-INF within your web app.
If you use Maven or Gradle you have to create it at src/main/webapp/META-INF/context.xml:
my-tomcat-app
src
main
java
resources
webapp
META-INF
context.xml
And give it the following contents:
<?xml version='1.0' encoding='utf-8'?>
<Context>
<Resource name="jdbc/boxfuse" auth="Container" type="javax.sql.DataSource" driverClassName="org.postgresql.Driver"
url="${BOXFUSE_DATABASE_URL}" username="${BOXFUSE_DATABASE_USER}" password="${BOXFUSE_DATABASE_PASSWORD}"/>
</Context>
You can now refer to it from your code in any way you like. For example:
DataSource dataSource = (DataSource) new InitialContext().lookup("java:comp/env/jdbc/boxfuse");
Using an existing database
To disable database auto-provisioning and use an existing database set db.type to none when creating your app.
Java Agents
If you wish to launch the JRE with one or more Java Agents, simply place the Java Agent files inside the war file under
/WEB-INF/javaagents/. In a Maven or Gradle project this means you have to put your agent jar and whatever other files it requires under src/main/webapp/WEB-INF/javaagents:
my-tomcat-app
src
main
java
resources
webapp
WEB-INF
javaagents
myjavaagent.jar
myjavaagent.properties
CloudCaptain will then automatically configure the JRE to use these Java Agents
JVM Memory
By default CloudCaptain will dynamically configure your JVM heap to use 85% of the available memory in the instance. All other settings
use the JVM defaults. You can override this by specifying the required JVM arguments like -Xmx via the
jvm.args configuration setting.
Temporary Files
CloudCaptain configures the JVM to use /tmp as the directory to store temporary files and provisions 1 GB of space by default.
To increase this (up to a maximum of 16 TB), simply set
the tmp configuration setting to the number of GB of temp space you need. To prevent CloudCaptain from
provisioning any temp space set tmp to 0.
Debugging
Remote debugging (including hot-code replace) with your favorite IDE is fully supported. Details and setup instructions on our debugging page.
Profiling
Profiling with tools like JVisualVM and Java Flight Recorder is fully supported. Details and setup instructions on our profiling page.
Live Reloading
CloudCaptain supports Live Reloading of exploded war files.
Time Zone
By default all CloudCaptain instance use the UTC time zone.
We don't recommend changing this as this greatly simplifies time zone issues in machine to machine communication and cleanly relegates all time zones related aspects to a pure presentation layer concern.
If however you still do want to change this, you can override the default time zone of the instance using the
TZ environment variable. For example to change the time zone of your instance to America/Los_Angeles
you would do so like this:
> boxfuse fuse -envvars.TZ=America/Los_Angeles
Native binaries and libs
Some JVM applications also depend on native Linux x64 binaries and libs to do their work. CloudCaptain makes it easy to integrate them into your image.
Simply place your binaries under WEB-INF/native/bin inside your war file and CloudCaptain
will automatically add them to the PATH at runtime in your instances.
If those binaries also depend on additional shared libraries beyond the C library, place the .so files of your libraries
under WEB-INF/native/lib inside your war file and CloudCaptain
will automatically add them to the LD_LIBRARY_PATH at runtime in your instances.
Tip
To list all the shared libraries your Linux x64 binary requires, you can use the following command on a Linux system:
$ ldd -v my-native-binary
If you use Maven or Gradle, the native directory should be put into the src/main/webapp/WEB-INF
directory. CloudCaptain will then automatically configure the PATH and LD_LIBRARY_PATH to use it.
my-tomcat-app
src
main
java
webapp
WEB-INF
native
bin
my-native-binary
other-linux-x64-binary
lib
my-shared-lib.so
other-shared-lib.so
You can then simply invoke them in your code using
Runtime.getRuntime().exec("my-native-binary arg1 arg2 arg3");
New Relic support
To monitor your app using New Relic simply pass in your New Relic license key when fusing your image and CloudCaptain will automatically install and configure the New Relic Servers Linux x64 and New Relic Java agents for you.
> boxfuse fuse -newrelic.licensekey=0123456789abcdef0123456789abcdef01234567
Alternatively you can also supply a newrelic.yml configuration file for the Java agent and CloudCaptain will
automatically use that instead. CloudCaptain will then install the agent for you, but won't override any application name you may have configured.
If you haven't configured a New Relic license key as described above, CloudCaptain will use
the license key contained in your newrelic.yml configuration file instead.
If you use Maven or Gradle, the newrelic.yml file should be put into the src/main/webapp/WEB-INF directory.
CloudCaptain will then automatically configure the New Relic Java agent to use it.
my-tomcat-app
src
main
java
resources
webapp
WEB-INF
newrelic.yml
Linux Kernel Tuning (experts only)
Kernel arguments
To tune the arguments passed Linux kernel from the bootloader, simply pass them using the
-linux.args setting when fusing your image.
sysctl.conf
If you need to tune the Linux kernel running in your instance, simply place a sysctl.conf file inside your war file under /WEB-INF.
In a Maven or Gradle project this means you have to put it under src/main/webapp/WEB-INF:
my-tomcat-app
src
main
java
resources
webapp
WEB-INF
sysctl.conf
You can then for example tune the maximum number of file descriptors by simply including the following in sysctl.conf:
fs.file-max = 131072
CloudCaptain will then automatically configure the Linux kernel to use these settings.