Hello everyone,
sooo, 7 days past and a lot has happend, the culmination of which is that I can now indeed connect to a running EXA8 instance (with certain limitations) 
But let´s start where we last left off:
After reading @Bogdan_Mihai input I very much suspected that the missing storage is our culprit, in combination with my confusion about “pubic IP” - in order to get around any uninstall shenanigans I simply restored OS- and DataDisk in Azure from a RestorePoint I set right before I did the c4 based install ( we skip the part where I forgot to enlarge the /home directory leading to many fun “not enough space” messages during install and jump right to the 2nd try ).
With my eduvm-01 now armed with a 16GB DataDisk ( and the necessary lvm actions done ), a secondary network interface attached ( for the external_addr ) and adjusted config-file ( external_addr now carried the seconds NIC instead of the “public IP” assigned through Azure ) I was ready to repeat the install - went right through, and this time, after we were done installing, a call to “c4 ps” yielded a progressively positive progress on our cluster stage up to “d”, meaning “database up and connectable”.
Still don´t quite understand why calling the copied c4 yields a different output than the “original one”, as in:
[exasol@eduvm-01 ~]$ ./c4 ps
WARN[2025-11-10 20:27:53] in ps.NewLister: in aws.NewConfigFromConfig: credentials file does not exist: /home/exasol/.aws/credentials module=awscf
WARN[2025-11-10 20:27:53] in ps.NewLister: in aws.NewConfigFromConfig: credentials file does not exist: /home/exasol/.aws/credentials module=aws
N PLAY_ID NODE MEDIUM INSTANCE DB_VERSION EXTERNAL_IP INTERNAL_IP STAGE STATE UPTIME TTL
1 fb5aed03 11 local - 2025.1.0 - 10.0.0.4 a1 - 00:38:49 +∞
[exasol@eduvm-01 ~]$ c4 ps
N PLAY_ID NODE MEDIUM INSTANCE DB_VERSION EXTERNAL_IP INTERNAL_IP STAGE STATE UPTIME TTL
1 fb5aed03 11 host - 2025.1.0 10.0.100.4 10.0.0.4 d - 00:38:55 +∞
2 fb5aed03 11 local - 2025.1.0 - 10.0.0.4 d - 00:38:54 +∞
As for the systemctl output, that also turned out to be a bit of a conundrum - at the “host” level, we got
[exasol@eduvm-01 ~]$ systemctl --user status c4_cloud_command
Failed to connect to bus: No medium found
Also didn´t change with the “magic word” ( i.e. sudo ).
Within the COS systemctl doesn´t exist:
[exasol@eduvm-01 ~]$ c4 connect -t 1/cos
Last login: Mon Nov 10 21:13:38 2025 from 10.0.100.4
root@n11:~# systemctl --user status c4_cloud_command
-bash: systemctl: command not found
Trying that is more due to my lack of knowledge, if I understand it correctly, then c4 ( and by extension c4_cloud_command ) is kind of an isolation layer so it would only make sense for it to only be present on the actual “host” layer.
With a bit of research work I dug up somthing that at least yielded an output, and presumably attests to the fact that “all is running well”:
[exasol@eduvm-01 ~]$ sudo systemctl --user -M exasol@ status c4
● c4.service - c4 server
Loaded: loaded (/home/exasol/.config/systemd/user/c4.service; enabled; preset: disabled)
Active: active (running) since Mon 2025-11-10 19:49:14 UTC; 46min ago
Main PID: 1724
Tasks: 8 (limit: 100168)
Memory: 82.1M
CPU: 265ms
CGroup: /user.slice/user-1001.slice/user@1001.service/app.slice/c4.service
├─1724 /bin/bash /home/exasol/.ccc/ccc/etc/c4
└─1727 /home/exasol/.ccc/ccc/bin/c4 server --socket /home/exasol/.ccc/ccc/etc/c4_socket
[exasol@eduvm-01 ~]$ sudo systemctl --user -M exasol@ status c4_cloud_command
● c4_cloud_command.service - c4 init service
Loaded: loaded (/home/exasol/.config/systemd/user/c4_cloud_command.service; enabled; preset: disabled)
Active: active (running) since Mon 2025-11-10 19:49:14 UTC; 46min ago
Main PID: 1725
Tasks: 651 (limit: 100168)
Memory: 1.4G
CPU: 41min 367ms
CGroup: /user.slice/user-1001.slice/user@1001.service/app.slice/c4_cloud_command.service
├─ 1725 /bin/bash /home/exasol/.ccc/ccc/etc/c4_cloud_command
├─ 2065 /home/exasol/.ccc/ccc/bin/c4 play @exasol-2025.1.0
├─ 2103 bash -c “main ‘@exasol-2025.1.0’”
├─ 2900 python3 /home/exasol/.ccc/x/u/branchr/saas-650d33b7-64r/.c4/play start
├─ 3073 python3 /home/exasol/.ccc/x/u/branchr/cos+86168de4-95cb568b-64r/.c4/play start
├─ 3254 /home/exasol/.ccc/x/u/branchr/cos+86168de4-95cb568b-64r/install/opt/exasol/cos-8.60.3/sbin/exact mount /home/exasol/.ccc/play/local/fb5aed03-6f45-433e-9b51-e6fbdae2e1b5/main/11/changes /home/exasol/.ccc/play/local/fb5aed03-6f45-433e-9b51-e6fbdae2e1b5/main/11/root /home/exasol/.ccc/play/local/fb5aed03-6f45-433e-9b51-e6fbdae2e1b5/main/11/data init-sc -i 11
├─ 3255 /opt/exasol/cos-8.60.3/libexec/cos_cored -n 11 --auth-sock-dir /var/lock -m 224.0.0.1 -s 10.0.0.4 -t 3250 -l /exa/logs/cored --node-uuid FB5AED036F45433E9B51E6FBDAE2E1B500000011 --default-file-mode 600 --with-strict-node-id --allow-only-same-subnet --canary-timeout=90 --canary-grace-period=300 --random=/exa/etc/cored_random /opt/exasol/cos-8.60.3/bin/exainit stage2
├─ 3264 tail -n0 -q -F /exa/logs/cored/exainit.log /exa/logs/cored/cored.log
├─ 3279 /opt/exasol/cos-8.60.3/bin/python3_cos /opt/exasol/cos-8.60.3/libexec/super_cored -d -a
├─ 3512 “sshd: /usr/sbin/sshd -D [listener] 0 of 300-800 startups”
├─ 3515 /usr/sbin/cron -f “-L 15”
├─ 3516 /opt/exasol/cos-8.60.3/libexec/logd --default-log-dir /exa/logs/logd
├─ 3517 /opt/exasol/cos-8.60.3/libexec/lockd
├─ 3563 /opt/exasol/cos-8.60.3/bin/python3_cos /opt/exasol/cos-8.60.3/libexec/bucketfsd --config=/exa/etc/bucketfs.cfg_bfsdefault
├─ 3565 /opt/exasol/cos-8.60.3/bin/python3_cos /opt/exasol/cos-8.60.3/bin/healthd
├─ 3566 /opt/exasol/cos-8.60.3/libexec/dwad --backupfile /exa/metadata/dwad/dwad.dump --store-config /exa/metadata/dwad/dwad.dump --store-interval 10 --allow-runtime-rename=cluster --upgrade-cluster-uuid-mapping=Exasol:hu5xANVgRoaEPBYEgX-jFg
├─ 3635 /opt/exasol/cos-8.60.3/libexec/cos_storage /exa/etc/cos_storage.conf
├─ 3723 /opt/exasol/cos-8.60.3/bin/python3_cos /opt/exasol/cos-8.60.3/bin/confd -v
├─ 3777 /opt/exasol/cos-8.60.3/share/webui_backend/db-restapi start --addr :4444 --disable-redirect --rpc-endpoint ``https://localhost:20003`` tls --certFile /exa/etc/ssl/ssl.crt --keyFile /exa/etc/ssl/ssl.key
├─ 3814 /opt/exasol/db-2025.1.0/bin/controller -dbName Exasol -current_cluster_name MAIN -current_cluster_uid hu5xANVgRoaEPBYEgX-jFg -commMain n11 -commNPROC 1 -port 8563 -mode rw -outputdir /exa/logs/db/Exasol/ -additionalAuthorizedSysPasswordHashes=OhNoYouDon´t -netmask= -auditing_enabled=1 -builtinScriptLanguageName=slc-9.5.2_c4_7_standard_EXASOL_all_r_4.4/Scr>
├─ 3850 /opt/exasol/db-2025.1.0/bin/pddserver -current_process_nr=1
├─ 3946 /opt/exasol/db-2025.1.0/bin/objectserver -current_process_nr=2
├─ 3995 /opt/exasol/db-2025.1.0/bin/exasqllog -current_process_nr=4
├─ 4023 /opt/exasol/db-2025.1.0/bin/loaderd -current_process_nr=5
├─ 4050 /opt/exasol/db-2025.1.0/bin/exaetl -current_process_nr=1024
├─ 4051 /opt/exasol/db-2025.1.0/bin/exacs -current_process_nr=3
├─ 4132 /opt/exasol/db-2025.1.0/bin/exasql -current_process_nr=7
├─ 4171 /opt/exasol/cos-8.60.3/bin/python3_cos /opt/exasol/cos-8.60.3/bin/eventd
├─ 4196 /opt/exasol/cos-8.60.3/bin/python3_cos /opt/exasol/cos-8.60.3/bin/rapid --wait-init --port 8000 --root-path /api/v1
├─ 4330 /opt/exasol/cos-8.60.3/bin/python3_cos -c “from multiprocessing.resource_tracker import main;main(114)”
├─ 97088 /usr/sbin/anacron -s
├─105193 /bin/sh -c “run-parts --report /etc/cron.daily”
├─105194 run-parts --report /etc/cron.daily
├─105198 /bin/sh /etc/cron.daily/apt-compat
├─105213 sleep 1352
└─106035 /opt/exasol/cos-8.60.3/bin/python3_cos /opt/exasol/cos-8.60.3/bin/confd_client db_list --json --volatile
And with all that, I could finally get some SQL going:
EXA: select substr(cluster_name,1,6) as cluster_name,to_char(measure_time,'…
CLUSTE MEASURE_TIME EVENT_TYPE DBMS_VERSION NODES DB_RAM_SIZE
MAIN 08.11.2025 12:09 STARTUP 2025.1.0 1 11.3
MAIN 08.11.2025 13:40 SHUTDOWN 2025.1.0 1 11.3
MAIN 10.11.2025 20:49 STARTUP 2025.1.0 1 11.3
3 rows in resultset.
Now I just need to figure out why this is only working with an EXAplus on the host itself, but not from a Windows-VM within the same subnet, even though the NetworkSecurityGroup should allow any traffic in the same vnet…oh well, we do have a running “cluster of one” at least, next short-term target is getting a screenshot from the new Admin-UI ( I already see the system listening on the corresponding port, so I can´t be that far off 
).
That´s it for now, hope this will help anyone trying anything similar to this, and I´ll keep updates coming.
Cheers,
-M.