how to postgres + java on debian 13 ? 😀
hostnamectl; # tested on Operating System: Debian GNU/Linux 13 (trixie) Kernel: Linux 6.12.74+deb13+1-amd64 Architecture: x86-64 su - root apt update apt install postgresql postgresql-contrib systemctl enable postgresql # what version was installed? psql --version psql (PostgreSQL) 17.9 (Debian 17.9-0+deb13u1) systemctl status postgresql ● postgresql.service - PostgreSQL RDBMS Loaded: loaded (/usr/lib/systemd/system/postgresql.service; enabled; preset: enabled) Active: active (exited) since Sun 2026-03-29 14:18:08 CEST; 2min 0s ago Invocation: 888ce00ab97344a4b6a11fdaec1b355c Main PID: 11146 (code=exited, status=0/SUCCESS) Mem peak: 1.9M CPU: 5ms pg_isready /var/run/postgresql:5432 - accepting connections # config /etc/postgresql/17/main/postgresql.conf # management systemctl start postgresql systemctl stop postgresql systemctl restart postgresql # usage sudo -u psql createuser user sudo -u postgres createdb -O user user_database1
# before login need to set password for default system and postgres user "postgres" # as root su - root # set a password for default system postgres user "postgres passwd postgres # become system user "postgres" su - postgres # change/reset password of user postgres psql -c "alter user postgres with password 'StrongPassword'" # alternatively su - postgres -c "psql -c \"alter user postgres with password 'postgres'\"" # login as user postgres # "postgres" user in postgres # is like "root" in linux psql -U postgres # login and select dbname psql -d dbname -U dbuser # login to a specific host with ip 127.0.0.1 psql -U dbuser -h 127.0.0.1 dbname # now the postgres interactive prompt should pop up # where use can enter commands psql (17.9 (Debian 17.9-0+deb13u1)) Type "help" for help. postgres=#
# if user gets error: psql: error: could not connect to server: FATAL: Ident authentication failed for user # edit this file vim /etc/postgresql/17/main/pg_hba.conf # TYPE DATABASE USER ADDRESS METHOD # "local" is for Unix domain socket connections only local all all md5 # IPv4 local connections: host all all 127.0.0.1/32 md5 # IPv6 local connections: host all all ::1/128 md5 # hit ESC # then :wq # write and quit in vim # restart postgres and try login again systemctl restart postgresql-12 # try login as postgres root user psql -U postgres Password for user postgres: psql (12.1) Type "help" for help. postgres=# <- YESSSS! LOGGED IN :) # list all databases \l List of databases Name | Owner | Encoding | Locale Provider | Collate | Ctype | Locale | ICU Rules | Access privileges -----------+----------+----------+-----------------+-------------+-------------+--------+-----------+----------------------- postgres | postgres | UTF8 | libc | en_US.UTF-8 | en_US.UTF-8 | | | template0 | postgres | UTF8 | libc | en_US.UTF-8 | en_US.UTF-8 | | | =c/postgres + | | | | | | | | postgres=CTc/postgres template1 | postgres | UTF8 | libc | en_US.UTF-8 | en_US.UTF-8 | | | =c/postgres + | | | | | | | | postgres=CTc/postgres (3 rows) # create new user CREATE USER dbuser WITH PASSWORD 'dbname'; # create new database CREATE DATABASE dbname ENCODING 'UTF-8' TEMPLATE template0 OWNER dbuser; # display short help \h # display extensive help \? General \copyright show PostgreSQL usage and distribution terms \crosstabview [COLUMNS] execute query and display results in crosstab \errverbose show most recent error message at maximum verbosity \g [FILE] or ; execute query (and send results to file or |pipe) \gdesc describe result of query, without executing it \gexec execute query, then execute each value in its result \gset [PREFIX] execute query and store results in psql variables \gx [FILE] as \g, but forces expanded output mode \q quit psql \watch [SEC] execute query every SEC seconds Help \? [commands] show help on backslash commands \? options show help on psql command-line options \? variables show help on special variables \h [NAME] help on syntax of SQL commands, * for all commands Query Buffer \e [FILE] [LINE] edit the query buffer (or file) with external editor \ef [FUNCNAME [LINE]] edit function definition with external editor \ev [VIEWNAME [LINE]] edit view definition with external editor \p show the contents of the query buffer \r reset (clear) the query buffer \s [FILE] display history or save it to file \w FILE write query buffer to file Input/Output \copy ... perform SQL COPY with data stream to the client host \echo [STRING] write string to standard output \i FILE execute commands from file \ir FILE as \i, but relative to location of current script \o [FILE] send all query results to file or |pipe \qecho [STRING] write string to query output stream (see \o) Conditional \if EXPR begin conditional block \elif EXPR alternative within current conditional block \else final alternative within current conditional block \endif end conditional block Informational (options: S = show system objects, + = additional detail) \d[S+] list tables, views, and sequences \d[S+] NAME describe table, view, sequence, or index \da[S] [PATTERN] list aggregates \dA[+] [PATTERN] list access methods \db[+] [PATTERN] list tablespaces \dc[S+] [PATTERN] list conversions \dC[+] [PATTERN] list casts \dd[S] [PATTERN] show object descriptions not displayed elsewhere \dD[S+] [PATTERN] list domains \ddp [PATTERN] list default privileges \dE[S+] [PATTERN] list foreign tables \det[+] [PATTERN] list foreign tables \des[+] [PATTERN] list foreign servers \deu[+] [PATTERN] list user mappings \dew[+] [PATTERN] list foreign-data wrappers \df[anptw][S+] [PATRN] list [only agg/normal/procedures/trigger/window] functions \dF[+] [PATTERN] list text search configurations \dFd[+] [PATTERN] list text search dictionaries \dFp[+] [PATTERN] list text search parsers \dFt[+] [PATTERN] list text search templates \dg[S+] [PATTERN] list roles \di[S+] [PATTERN] list indexes \dl list large objects, same as \lo_list \dL[S+] [PATTERN] list procedural languages \dm[S+] [PATTERN] list materialized views \dn[S+] [PATTERN] list schemas \do[S] [PATTERN] list operators \dO[S+] [PATTERN] list collations \dp [PATTERN] list table, view, and sequence access privileges \dP[itn+] [PATTERN] list [only index/table] partitioned relations [n=nested] \drds [PATRN1 [PATRN2]] list per-database role settings \dRp[+] [PATTERN] list replication publications \dRs[+] [PATTERN] list replication subscriptions \ds[S+] [PATTERN] list sequences \dt[S+] [PATTERN] list tables \dT[S+] [PATTERN] list data types \du[S+] [PATTERN] list roles \dv[S+] [PATTERN] list views \dx[+] [PATTERN] list extensions \dy [PATTERN] list event triggers \l[+] [PATTERN] list databases \sf[+] FUNCNAME show a function's definition \sv[+] VIEWNAME show a view's definition \z [PATTERN] same as \dp Formatting \a toggle between unaligned and aligned output mode \C [STRING] set table title, or unset if none \f [STRING] show or set field separator for unaligned query output \H toggle HTML output mode (currently off) \pset [NAME [VALUE]] set table output option (border|columns|csv_fieldsep|expanded|fieldsep| fieldsep_zero|footer|format|linestyle|null| numericlocale|pager|pager_min_lines|recordsep| recordsep_zero|tableattr|title|tuples_only| unicode_border_linestyle|unicode_column_linestyle| unicode_header_linestyle) \t [on|off] show only rows (currently off) \T [STRING] set HTML <table> tag attributes, or unset if none \x [on|off|auto] toggle expanded output (currently off) Connection \c[onnect] {[DBNAME|- USER|- HOST|- PORT|-] | conninfo} connect to new database (currently "cyclos4") \conninfo display information about current connection \encoding [ENCODING] show or set client encoding \password [USERNAME] securely change the password for a user Operating System \cd [DIR] change the current working directory \setenv NAME [VALUE] set or unset environment variable \timing [on|off] toggle timing of commands (currently off) \! [COMMAND] execute command in shell or start interactive shell Variables \prompt [TEXT] NAME prompt user to set internal variable \set [NAME [VALUE]] set internal variable, or list all if no parameters \unset NAME unset (delete) internal variable Large Objects \lo_export LOBOID FILE \lo_import FILE [COMMENT] \lo_list \lo_unlink LOBOID large object operations
# use Ctrl+D # or type \q # to quit/logoff postgres
install tomcat
su - root apt update # install java apt install default-jdk # check what version was installed java --version openjdk 21.0.10 2026-01-20 OpenJDK Runtime Environment (build 21.0.10+7-Debian-1deb13u1) OpenJDK 64-Bit Server VM (build 21.0.10+7-Debian-1deb13u1, mixed mode, sharing) # add tomcat user and group groupadd tomcat useradd -s /bin/false -g tomcat -d /opt/tomcat tomcat mkdir /home/user/software/tomcat cd /home/user/software/tomcat # tomcat 11.0.20 requires java 17 wget https://downloads.apache.org/tomcat/tomcat-11/v11.0.20/bin/apache-tomcat-11.0.20.tar.gz mkdir /opt/tomcat tar xzvf apache-tomcat-11.0.20.tar.gz -C /opt/tomcat --strip-components=1 chgrp -R tomcat /opt/tomcat cd /opt/tomcat # give tomcat group read access to conf directory and all of its contents # and execute access to the directory itself chmod -R g+r conf chmod g+x conf chown -R tomcat webapps/ work/ temp/ logs/ # where is java installed? update-java-alternatives -l java-1.21.0-openjdk-amd64 2111 /usr/lib/jvm/java-1.21.0-openjdk-amd64 # need to set $JAVA_HOME environment variable (will only be active after reboot) echo 'JAVA_HOME="/usr/lib/jvm/java-1.21.0-openjdk-amd64"' >> /etc/profile # create service file for tomcat vim /etc/systemd/system/tomcat.service [Unit] Description=Apache Tomcat Web Application Container After=network.target [Service] Type=forking Environment=JAVA_HOME=/usr/lib/jvm/java-1.21.0-openjdk-amd64 Environment=CATALINA_PID=/opt/tomcat/temp/tomcat.pid Environment=CATALINA_HOME=/opt/tomcat Environment=CATALINA_BASE=/opt/tomcat Environment='CATALINA_OPTS=-Xms512M -Xmx1024M -server -XX:+UseParallelGC' Environment='JAVA_OPTS=-Djava.awt.headless=true -Djava.security.egd=file:/dev/./urandom' ExecStart=/opt/tomcat/bin/startup.sh ExecStop=/opt/tomcat/bin/shutdown.sh User=tomcat Group=tomcat UMask=0007 RestartSec=10 Restart=always [Install] WantedBy=multi-user.target
# make systemd aware of the new service file systemctl daemon-reload # start it systemctl start tomcat systemctl status tomcat ● tomcat.service - Apache Tomcat Web Application Container Loaded: loaded (/etc/systemd/system/tomcat.service; disabled; preset: enabled) Active: active (running) since Sun 2026-03-29 16:06:12 CEST; 4s ago Invocation: 21cb70809f8e4134b711fe2ee96d1f49 Process: 4680 ExecStart=/opt/tomcat/bin/startup.sh (code=exited, status=0/SUCCESS) Main PID: 4687 (java) Tasks: 32 (limit: 4629) Memory: 179.6M (peak: 182.5M) CPU: 2.470s CGroup: /system.slice/tomcat.service └─4687 /usr/lib/jvm/java-1.21.0-openjdk-amd64/bin/java -Djava.util.logging.config.file=/opt/tomcat/conf/logging.properties -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Djava.awt.headless=true -Djava.security.egd=file:/dev/./urandom -Djd> Mar 29 16:06:12 debian13-desktop systemd[1]: Starting tomcat.service - Apache Tomcat Web Application Container... Mar 29 16:06:12 debian13-desktop startup.sh[4680]: Tomcat started. Mar 29 16:06:12 debian13-desktop systemd[1]: Started tomcat.service - Apache Tomcat Web Application Container.
# make it auto start
systemctl enable tomcat
echo $JAVA_HOME
/usr/lib/jvm/java-1.21.0-openjdk-amd64
test:
open browser and browser to: http://localhost:8080/
it should show this welcome screen
debug: follow the logs
# activate web gui management user sed -i '/<\/tomcat-users>/i \ <user username="tomcat" password="tomcat" roles="manager-gui,manager-script,manager-status,admin-gui,admin-script"/>' /opt/tomcat/conf/tomcat-users.xml # watch the logs cd /scripts wget https://dwaves.de/software/python/colorize.py.txt mv colorize.py.txt colorize.py vim /scripts/mon_all_logs_in_color.sh find -L /var/log/* -type f \( -name "*" \) ! -path '*.gz*' -exec tail -n0 -f {} + | /usr/bin/python3 /scripts/colorize.py & find -L /opt/tomcat/logs/* -type f \( -name "*" \) ! -path '*.gz*' -exec tail -n0 -f {} + | /usr/bin/python3 /scripts/colorize.py & chmod +x /scripts/*.sh chmod +x /scripts/*.py # run it /scripts/mon_all_logs_in_color.sh # now when root does this, there should be A LOT of new log lines generated and instantly showing up on the screen :D systemctl restart tomcat
there should also be a management web gui
# backup cp -rv /opt/tomcat/conf/tomcat-users.xml /opt/tomcat/conf/tomcat-users.xml.backup # activate web gui management user "tomcat" with password "tomcat" (only for test systems! for production systems please change!) # manager-gui = allows access to HTML GUI and status pages http://localhost:8080/manager/html# manager-script = allows access to the HTTP API and status pages # manager-jmx = allows access to the JMX proxy and the status pages # manager-status = allows access status pages http://localhost:8080/manager/status
Links:
- debug problems: follow the logs… https://dwaves.de/2017/06/15/gnu-linux-monitor-all-logs-live-real-time-follow-all-show-changes-to-log-files-under-var-log-keyword-highlighting-for-log-files/
- backup & restore: https://dwaves.de/2020/05/25/howto-postgres-multi-threaded-backup-and-restore/
- https://www.digitalocean.com/community/tutorials/how-to-install-apache-tomcat-9-on-debian-10
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