He was looking at options for ensure that the drivers can be updated to match the target DB2 runtime, without needing to rebuild the entire WebSphere Liberty Profile image each and every time.
There are a number of approaches, including storing the drivers on an external ( to the image/container ) file-system, using a Docker volume.
As an example, something like this: -
docker run -v /host/directory:/container/directory image
In the absence of volumes, we could configure the container to reach out to an external file/web-server at boot-time ( akin to a bootstrap service )
As an alternative, we considered an approach where the image hosting WebSphere Liberty Profile references the JDBC drivers from a DIFFERENT image when it's built, meaning that we CAN rebuild the Liberty image without a huge amount of impact upon the size/layers of the Liberty image itself.
This approach seemed to work ....
I started by pulling the requisite images: -
docker pull websphere-liberty
docker pull store/ibmcorp/db2_developer_c:11.1.4.4-s390x
and created an environment file to start the DB2 instance within its own container: -
vi ~/.envlist
LICENSE=accept
DB2INSTANCE=db2inst1
DB2INST1_PASSWORD=passw0rd
TO_CREATE_SAMPLEDB=true
and started the DB2 database container: -
db2=`docker run -h db2server --name db2server --restart=always --detach --privileged=true -p 50000:50000 -p 55000:55000 --env-file ~/.envlist -v /db2data:/database store/ibmcorp/db2_developer_c:11.1.4.4-s390x`
and checked the logs until DB2 came up: -
docker logs $db2 -f
...
07/19/2019 19:10:30 0 0 SQL1063N DB2START processing was successful.
SQL1063N DB2START processing was successful.
(*) Starting TEXT SEARCH service ...
CIE00001 Operation completed successfully.
...
and then logged into the running container: -
docker exec -it $db2 /bin/bash
and switched to the db2inst1 user: -
su - db2inst1
Last login: Mon Jul 22 13:44:17 UTC 2019
and listed the DB directory: -
db2 list db directory
System Database Directory
Number of entries in the directory = 1
Database 1 entry:
Database alias = SAMPLE
Database name = SAMPLE
Local database directory = /database/config/db2inst1
Database release level = 14.00
Comment =
Directory entry type = Indirect
Catalog database partition number = 0
Alternate server hostname =
Alternate server port number =
and connected to the SAMPLE DB: -
db2 connect to sample
Database Connection Information
Database server = DB2/LINUXZ64 11.1.4.4
SQL authorization ID = DB2INST1
Local database alias = SAMPLE
and query the EMPLOYEE table: -
db2 'select * from employee'
EMPNO FIRSTNME MIDINIT LASTNAME WORKDEPT PHONENO HIREDATE JOB EDLEVEL SEX BIRTHDATE SALARY BONUS COMM
------ ------------ ------- --------------- -------- ------- ---------- -------- ------- --- ---------- ----------- ----------- -----------
000010 CHRISTINE I HAAS A00 3978 01/01/1995 PRES 18 F 08/24/1963 152750.00 1000.00 4220.00
000020 MICHAEL L THOMPSON B01 3476 10/10/2003 MANAGER 18 M 02/02/1978 94250.00 800.00 3300.00
000030 SALLY A KWAN C01 4738 04/05/2005 MANAGER 20 F 05/11/1971 98250.00 800.00 3060.00
000050 JOHN B GEYER E01 6789 08/17/1979 MANAGER 16 M 09/15/1955 80175.00 800.00 3214.00
000060 IRVING F STERN D11 6423 09/14/2003 MANAGER 16 M 07/07/1975 72250.00 500.00 2580.00
000070 EVA D PULASKI D21 7831 09/30/2005 MANAGER 16 F 05/26/2003 96170.00 700.00 2893.00
000090 EILEEN W HENDERSON E11 5498 08/15/2000 MANAGER 16 F 05/15/1971 89750.00 600.00 2380.00
000100 THEODORE Q SPENSER E21 0972 06/19/2000 MANAGER 14 M 12/18/1980 86150.00 500.00 2092.00
000110 VINCENZO G LUCCHESSI A00 3490 05/16/1988 SALESREP 19 M 11/05/1959 66500.00 900.00 3720.00
000120 SEAN O'CONNELL A00 2167 12/05/1993 CLERK 14 M 10/18/1972 49250.00 600.00 2340.00
000130 DELORES M QUINTANA C01 4578 07/28/2001 ANALYST 16 F 09/15/1955 73800.00 500.00 1904.00
000140 HEATHER A NICHOLLS C01 1793 12/15/2006 ANALYST 18 F 01/19/1976 68420.00 600.00 2274.00
000150 BRUCE ADAMSON D11 4510 02/12/2002 DESIGNER 16 M 05/17/1977 55280.00 500.00 2022.00
000160 ELIZABETH R PIANKA D11 3782 10/11/2006 DESIGNER 17 F 04/12/1980 62250.00 400.00 1780.00
000170 MASATOSHI J YOSHIMURA D11 2890 09/15/1999 DESIGNER 16 M 01/05/1981 44680.00 500.00 1974.00
000180 MARILYN S SCOUTTEN D11 1682 07/07/2003 DESIGNER 17 F 02/21/1979 51340.00 500.00 1707.00
000190 JAMES H WALKER D11 2986 07/26/2004 DESIGNER 16 M 06/25/1982 50450.00 400.00 1636.00
000200 DAVID BROWN D11 4501 03/03/2002 DESIGNER 16 M 05/29/1971 57740.00 600.00 2217.00
000210 WILLIAM T JONES D11 0942 04/11/1998 DESIGNER 17 M 02/23/2003 68270.00 400.00 1462.00
000220 JENNIFER K LUTZ D11 0672 08/29/1998 DESIGNER 18 F 03/19/1978 49840.00 600.00 2387.00
000230 JAMES J JEFFERSON D21 2094 11/21/1996 CLERK 14 M 05/30/1980 42180.00 400.00 1774.00
000240 SALVATORE M MARINO D21 3780 12/05/2004 CLERK 17 M 03/31/2002 48760.00 600.00 2301.00
000250 DANIEL S SMITH D21 0961 10/30/1999 CLERK 15 M 11/12/1969 49180.00 400.00 1534.00
000260 SYBIL P JOHNSON D21 8953 09/11/2005 CLERK 16 F 10/05/1976 47250.00 300.00 1380.00
000270 MARIA L PEREZ D21 9001 09/30/2006 CLERK 15 F 05/26/2003 37380.00 500.00 2190.00
000280 ETHEL R SCHNEIDER E11 8997 03/24/1997 OPERATOR 17 F 03/28/1976 36250.00 500.00 2100.00
000290 JOHN R PARKER E11 4502 05/30/2006 OPERATOR 12 M 07/09/1985 35340.00 300.00 1227.00
000300 PHILIP X SMITH E11 2095 06/19/2002 OPERATOR 14 M 10/27/1976 37750.00 400.00 1420.00
000310 MAUDE F SETRIGHT E11 3332 09/12/1994 OPERATOR 12 F 04/21/1961 35900.00 300.00 1272.00
000320 RAMLAL V MEHTA E21 9990 07/07/1995 FIELDREP 16 M 08/11/1962 39950.00 400.00 1596.00
000330 WING LEE E21 2103 02/23/2006 FIELDREP 14 M 07/18/1971 45370.00 500.00 2030.00
000340 JASON R GOUNOT E21 5698 05/05/1977 FIELDREP 16 M 05/17/1956 43840.00 500.00 1907.00
200010 DIAN J HEMMINGER A00 3978 01/01/1995 SALESREP 18 F 08/14/1973 46500.00 1000.00 4220.00
200120 GREG ORLANDO A00 2167 05/05/2002 CLERK 14 M 10/18/1972 39250.00 600.00 2340.00
200140 KIM N NATZ C01 1793 12/15/2006 ANALYST 18 F 01/19/1976 68420.00 600.00 2274.00
200170 KIYOSHI YAMAMOTO D11 2890 09/15/2005 DESIGNER 16 M 01/05/1981 64680.00 500.00 1974.00
200220 REBA K JOHN D11 0672 08/29/2005 DESIGNER 18 F 03/19/1978 69840.00 600.00 2387.00
200240 ROBERT M MONTEVERDE D21 3780 12/05/2004 CLERK 17 M 03/31/1984 37760.00 600.00 2301.00
200280 EILEEN R SCHWARTZ E11 8997 03/24/1997 OPERATOR 17 F 03/28/1966 46250.00 500.00 2100.00
200310 MICHELLE F SPRINGER E11 3332 09/12/1994 OPERATOR 12 F 04/21/1961 35900.00 300.00 1272.00
200330 HELENA WONG E21 2103 02/23/2006 FIELDREP 14 F 07/18/1971 35370.00 500.00 2030.00
200340 ROY R ALONZO E21 5698 07/05/1997 FIELDREP 16 M 05/17/1956 31840.00 500.00 1907.00
42 record(s) selected.
Having validated that the DB2 container was clean-and-green, I then proceeded to download a recent set of DB2 JDBC drivers from here: -
and extracted the relevant JARs to a newly created subdirectory: -
mkdir /db2jars
tar xzvf /tmp/v11.1.4fp4_jdbc_sqlj.tar.gz -C /tmp
unzip /tmp/jdbc_sqlj/db2_db2driver_for_jdbc_sqlj.zip -d /tmp
cp /tmp/db2jcc.jar /db2jars
cp /tmp/db2jcc4.jar /db2jars
and then created a TAR file containing those JARs: -
tar cvf dependency.tar /db2jars
I then created a Dockerfile: -
vi Dockerfile.DB2
FROM scratch
ADD dependency.tar /
and built an image: -
docker build -t db2jars:latest -f ~/Dockerfile.DB2 .
Sending build context to Docker daemon 1.459GB
Step 1/2 : FROM scratch
--->
Step 2/2 : ADD dependency.tar /
---> d7cfd446014e
Successfully built d7cfd446014e
Successfully tagged db2jars:latest
which gave me a Docker image: -
docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
db2jars latest 69deb549f3f0 5 days ago 8.05MB
I then created a second Dockerfile, for WebSphere Liberty Profile: -
vi ~/Dockerfile.WLP
FROM websphere-liberty:latest
ENV LICENSE accept
COPY --from=db2jars:latest /db2jars /db2jars
COPY JdbcTestDB2.class /
CMD ["java","-cp","/:/db2jars/db2jcc.jar","JdbcTestDB2","172.18.10.190","50000","sample","db2inst1 ","passw0rd"]
and built the image: -
docker build -t wlp:latest -f ~/Dockerfile.WLP .
Sending build context to Docker daemon 1.459GB
Step 1/5 : FROM websphere-liberty:latest
---> 5005e127f3b4
Step 2/5 : ENV LICENSE accept
---> Using cache
---> 4fb20054c1b4
Step 3/5 : COPY --from=db2jars:latest /db2jars /db2jars
---> Using cache
---> 7e7ba23d46d4
Step 4/5 : COPY JdbcTestDB2.class /
---> Using cache
---> ffe1ef5dca2c
Step 5/5 : CMD ["java","-cp","/:/db2jars/db2jcc.jar","JdbcTestDB2","172.18.10.190","50000","sample","db2inst1 ","Qp455w0rd"]
---> Using cache
---> 490fac5dabe4
Successfully built 490fac5dabe4
Successfully tagged wlp:latest
I then instantiated the container: -
wlp=`docker run -d -t -p 80:9080 -p 443:9443 wlp:latest`
and checked the logs: -
docker logs $wlp -f
000010 CHRISTINE HAAS
000020 MICHAEL THOMPSON
000030 SALLY KWAN
000050 JOHN GEYER
000060 IRVING STERN
000070 EVA PULASKI
000090 EILEEN HENDERSON
000100 THEODORE SPENSER
000110 VINCENZO LUCCHESSI
000120 SEAN O'CONNELL
000130 DELORES QUINTANA
000140 HEATHER NICHOLLS
000150 BRUCE ADAMSON
000160 ELIZABETH PIANKA
000170 MASATOSHI YOSHIMURA
000180 MARILYN SCOUTTEN
000190 JAMES WALKER
000200 DAVID BROWN
000210 WILLIAM JONES
000220 JENNIFER LUTZ
000230 JAMES JEFFERSON
000240 SALVATORE MARINO
000250 DANIEL SMITH
000260 SYBIL JOHNSON
000270 MARIA PEREZ
000280 ETHEL SCHNEIDER
000290 JOHN PARKER
000300 PHILIP SMITH
000310 MAUDE SETRIGHT
000320 RAMLAL MEHTA
000330 WING LEE
000340 JASON GOUNOT
200010 DIAN HEMMINGER
200120 GREG ORLANDO
200140 KIM NATZ
200170 KIYOSHI YAMAMOTO
200220 REBA JOHN
200240 ROBERT MONTEVERDE
200280 EILEEN SCHWARTZ
200310 MICHELLE SPRINGER
200330 HELENA WONG
200340 ROY ALONZO
Magic has occurred ....
For the record, the reason that this happens is in the last line of Dockerfile.WLP: -
...
CMD ["java","-cp","/:/db2jars/db2jcc.jar","JdbcTestDB2","172.18.10.190","50000","sample","db2inst1 ","passw0rd"]
...
which uses this Java class: -
JdbcTestDB2.java
import java.sql.Connection ;
import java.sql.DriverManager ;
import java.sql.ResultSet ;
import java.sql.Statement ;
import java.sql.SQLException;
class JdbcTestDB2
{
public static void main (String args[])
{
try
{
Class.forName("com.ibm.db2.jcc.DB2Driver");
}
catch (ClassNotFoundException e)
{
System.err.println (e) ;
System.exit (-1) ;
}
String hostname = args[0];
String port = args[1];
String dbName = args[2];
String userName = args[3];
String password = args[4];
String sslConnection = "false";
java.util.Properties properties = new java.util.Properties();
properties.put("user",userName);
properties.put("password", password);
String url = "jdbc:db2://" + hostname + ":" + port + "/" + dbName;
try
{
Connection connection = DriverManager.getConnection(url,properties);
String query = "select EMPNO,FIRSTNME,LASTNAME from DB2INST1.EMPLOYEE" ;
Statement statement = connection.createStatement () ;
ResultSet rs = statement.executeQuery (query) ;
while ( rs.next () )
System.out.println (rs.getString (1) + " " + rs.getString(2) + " " + rs.getString(3)) ;
connection.close () ;
}
catch (java.sql.SQLException e)
{
System.err.println (e) ;
System.exit (-1) ;
}
}
}
to connect to the DB2 container, using the IP address of the box hosting the container, on port 50000 ( which is mapped from container to host when we start the DB2 container, via -p 50000:50000
So, when I'm ready to rev the DB2 drivers, I merely need to repeat the above steps to download them, TAR them up, create a new Docker image, and rebuild the WLP image, without making a huge impact upon the size / layers of the image itself.
As I said at the beginning, this is ONE way of solving the problem BUT FUN!!!!
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